You are an expert CBSE XII CS Computer Science teacher, examiner, and study material creator.

===========================================
SCOPE — READ BEFORE GENERATING ANYTHING
===========================================
Today's lecture covers ONE topic only: "Operators, precedence and expression evaluation"
Lecture number 3 of 91 | Duration: 35 minutes | Board: CBSE
Chapter: Computational Thinking and Programming – 2

HARD RULE: Every piece of content you generate — notes, examples, questions, tips —
must be directly relevant to "Operators, precedence and expression evaluation" only.
DO NOT pull content, examples, or questions from any other topic or chapter.

LECTURE MODE: THEORY / CONCEPT TEACHING
- Teach the concept first: definitions, intuition, examples, syntax/steps, and misconceptions.
- Use the given exam-frequency analysis internally to decide emphasis and short concept checks; keep the lecture concept-teaching focused.
- Keep content tightly scoped to today's concept list.

===========================================
SECTION 1: LECTURE INFORMATION
===========================================

Class: XII CS | Subject: Computer Science | Board: CBSE
Topic: Operators, precedence and expression evaluation Theory
Subtopics to cover today:
- Operators, precedence and expression evaluation

Student level: Class XII, CBSE Board, average to above-average students preparing for board exams

===========================================
SECTION 2: TEACHER'S REFERENCE NOTES
===========================================

Operators, precedence and expression evaluation Theory

Concept ID: U1_OPERATORS_EXPRESSIONS.
Primary Sub-subtopic: Operators, precedence and expression evaluation.
Question-bank grouping: Revision of Python & Core Concepts.

Use this lecture for theory, examples, misconceptions, and short concept checks mapped to this concept ID.

Teaching ideas: Teach the concept first, then use a small number of concept-ID matched concept checks.

===========================================
SECTION 3: EXAM FREQUENCY DATA (Year-wise)
===========================================

Teaching priority: HIGH
High-yield concepts: Operators precedence and expression evaluation

| Year | Questions | Marks |
|------|-----------|-------|
| 2021 | 1 | 1 |
| 2022 | 2 | 2 |
| 2023 | 6 | 6 |
| 2024 | 4 | 5 |
| 2025 | 9 | 12 |
| 2026 | 1 | 1 |
| **Total** | **23** | **27** |

===========================================
SECTION 4: EXAM ANALYSIS INPUT — DO NOT PRINT THESE IN THEORY NOTES
(Scope: "Operators, precedence and expression evaluation" only — 23 questions from board papers)
===========================================

THEORY LECTURE RULE: use these PYQs only as private analysis data — this lecture is PURELY THEORY.
- Cover every concept and trap revealed by these PYQs in the study notes
- Do NOT print, quote, reproduce, paraphrase, or label any actual PYQ in the final HTML
- Self-generate your own tricky/important questions and examples about the concept itself only —
  do not call them "PYQ-pattern", "PYQ-style", "board-style", or reference PYQs/previous years at all
- In theory lectures, generated questions must be MCQ or Short Answer only
- Never use the word "PYQ" or phrases like "previous year question" anywhere in the visible HTML


--- 2021 Board Exam (1 question | 1 marks) ---

Q1. [MCQ] [1M] [Easy] Section-B
Evaluate the following expression and identify the correct answer.
16 - (4 + 2) * 5 + 2**3 * 4
a) 54
b) 46
c) 18
d) 32

--- 2022 Board Exam (2 questions | 2 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Consider the given expression:
not True and False or True
Which of the following will be correct output if the given expression is evaluated?
a) True
b) False
c) NONE
d) NULL

Q2. [MCQ] [1M] [Easy] Section-A
What will the following expression be evaluated to in Python?
print(15.0 / 4 + (8 + 3.0))
a) 14.75
b) 14.0
c) 15
d) 15.5

--- 2023 Board Exam (6 questions | 6 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Consider the given expression :
5<10 and 12>7 or not 7>4
Which of the following will be the correct output, if the given expression is evaluated ?
(a) True
(b) False
(c) NONE
(d) NULL

Q2. [MCQ] [1M] [Easy] Section-A
Which of the following operators will return either True or False ?
(a) +=
(b) !=
(c) =
(d) x=

Q3. [MCQ] [1M] [Easy] Section-A
What will the following expression be evaluated to in Python ?
print (4+3*5/3-5%2)
(a) 8.5
(b) 8.0
(c) 10.2
(d) 10.0

Q4. [MCQ] [1M] [Easy] Section-A
Consider the given expression :
7<4 or 6>3 and not 10==10 or 17>4
Which of the following will be the correct output if the given expression is evaluated ?
(a) True
(b) False
(c) NONE
(d) NULL

Q5. [MCQ] [1M] [Easy] Section-A
Which of the following is an example of identity operators of Python ?
(a) is
(b) on
(c) in
(d) not in

Q6. [MCQ] [1M] [Easy] Section-A
What will the following expression be evaluated to in Python ?
print (6/3 + 4**3//8-4)
(a) 6.5
(b) 4.0
(c) 6.0
(d) 4

--- 2024 Board Exam (4 questions | 5 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Which of the following are the valid logical operators in Python ?
(A) and, or, not
(B) AND, OR, NOT
(C) &&, ||, !
(D) &, |, ~

Q2. [MCQ] [1M] [Easy] Section-A
What will be the output of the following statement ?
print(6+5/4**2//5+8)
(A) –14.0
(B) 14.0
(C) 14
(D) –14

Q3. [MCQ] [1M] [Easy] Section-A
Which of the following expressions evaluates to False?
a) not(True) and False
b) True or False
c) not(False and True)
d) True and not(False)

Q4. [Short Answer] [2M] [Easy] Section-B
Give two examples of each of the following:
(I) Arithmetic operators
(II) Relational operators

--- 2025 Board Exam (9 questions | 12 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
What will be the output of the following statement?
print(14%3**2*4)
(A) 16
(B) 64
(C) 20
(D) 256

Q2. [MCQ] [1M] [Easy] Section-A
Which of the following operator evaluates to True if the variable on either side of the operator points towards the same memory location and False otherwise?
(A) is
(B) is not
(C) and
(D) or

Q3. [MCQ] [1M] [Easy] Section-A
What is the value of the following expression ?
3 + 3.00, 3**3.0
(A) [6.0, 27.0]
(B) (6.0, 9.0)
(C) (6, 27)
(D) (6.0, 27.0)

Q4. [Short Answer] [1M] [Easy] Section-A
State whether the following statement is True or False.
In Python, the print() evaluates the expression before displaying it on the screen.

Q5. [MCQ] [1M] [Easy] Section-A
Consider the given expression:
print(19<11 and 29>19 or not 75>30)
Which of the following will be the correct output of the given expression?
a) True
b) False
c) Null
d) No output

Q6. [Output Prediction] [1M] [Easy] Section-A
What will be the output of the following Python statement:
print(10-3**2**2+144/12)

Q7. [Short Answer] [2M] [Easy] Section-B
Evaluate the expressions as asked in the questions (a) and (b) given below:

(a) Given A = -2 and B = 7, find:
A >= -3 or B > 10

(b) Given X = True, evaluate:
not X

Q8. [Short Answer] [2M] [Easy] Section-B
What is the difference between = and == in Python ? Give an example of each.

Q9. [Short Answer] [2M] [Easy] Section-B
Give an example of each of the following :
(i) An expression using any one identity operator.
(ii) An arithmetic expression which uses any one augmented assignment operator.

--- 2026 Board Exam (1 question | 1 marks) ---

Q1. [MCQ] [1M] [Easy] Section-A
Which of the following expressions in Python evaluates to True ?
(A) 2>3 and 2<3
(B) 3>1 and 2
(C) 3>1 and 3>2
(D) 3>1 and 3<2

===========================================
===========================================
QUESTION PATTERN BANK (What the board actually asks for THIS topic)
===========================================
Scope: ONLY questions for today's lecture topic are listed below.
DO NOT import questions from other topics or chapters.
These are concept-pattern summaries (what TYPE the board asks), not copies of the
actual questions — never reproduce full question text here.

### Concept: Operators precedence and expression evaluation
  Pattern: MCQ=17, Output Prediction=1, Short Answer=5 | Marks: 1M=19, 2M=4 | Total: 23 questions
  [MCQ] [1M] [Easy] × 9
    → Core concept of Operators precedence and expression evaluation
  [MCQ] [1M] [Easy] × 6
    → Output/result interpretation for the current concept
  [MCQ] [1M] [Easy] × 2
    → True/False: core concept of Operators precedence and expression evaluation
  [Short Answer] [2M] [Easy] × 4
    → Core concept of Operators precedence and expression evaluation
  [Short Answer] [1M] [Easy]
    → True/False: core concept of Operators precedence and expression evaluation
  [Output Prediction] [1M] [Easy]
    → Output/result interpretation for the current concept


===========================================
===========================================
IMPORTANCE ANALYSIS (allocate teaching time by this ranking)
===========================================
| Rank | Concept | Score | Times Tested | Total Marks | Recent Years | Priority |
|------|---------|-------|-------------|-------------|--------------|----------|
| 1 | Operators precedence and expression evaluation | 91 | 23 | 27M | 2026, 2025, 2024 | CRITICAL |

CRITICAL concepts → full sub-section + comparison table + 2 worked examples
HIGH concepts     → 1 sub-section + 1 worked example
MEDIUM concepts   → definition + 1 quick example only

===========================================
EXAMINER FINGERPRINT — TRAPS TO COVER INTERNALLY
===========================================

Use the exam-frequency input only for internal analysis. Do not print, quote, reproduce, paraphrase, or label any actual board question in the final HTML.

For this lecture, the generated teaching material must strongly cover these traps:

No static trap list exists yet for "Operators, precedence and expression evaluation". Self-generate 4–7 traps from:
- actual question patterns for Operators precedence and expression evaluation
- common wrong assumptions students make about this concept
- output-tracing traps
- syntax-vs-runtime traps
- comparison traps
- order/sequence traps

Important: this list should be treated as dynamic — for lectures with no static trap list, generate traps yourself from the categories above rather than leaving this section thin.
===========================================
YOUR TASK — Generate a complete classroom-ready teaching package
===========================================

Output format: FULL HTML (print-ready, A4, same format as CBSE study material).
Use the CSS classes below. NO plain Markdown — use HTML elements only.

HTML STRUCTURE TO GENERATE:

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>Operators, precedence and expression evaluation Theory — Lecture 3</title>
<style>
/* ── PRINT SETUP ── */
@page { size: A4; margin: 12mm 14mm 12mm 14mm; }
* { box-sizing: border-box; }

/* ── BASE ── */
body { font-family: 'Segoe UI', Arial, sans-serif; font-size: 9.5pt; color: #1a1a2e; line-height: 1.4; background: #fff; margin: 0; padding: 0; }

/* ── HEADINGS ── */
h1 { font-size: 17pt; text-align: center; color: #16213e; border-bottom: 3px solid #e94560; padding-bottom: 5px; margin: 0 0 8px; }
h2 { font-size: 12pt; color: #0f3460; background: linear-gradient(90deg,#e8f4f8,#fff); padding: 5px 10px; margin: 14px 0 6px; border-left: 5px solid #e94560; }
h3 { font-size: 10.5pt; color: #16213e; border-bottom: 1.5px dashed #ccc; padding-bottom: 3px; margin: 10px 0 4px; }

/* ── CONTENT BOXES ── */
.def-box { background:#e3f2fd; border-left:3px solid #1976d2; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.key-box { background:#fff8e1; border-left:3px solid #f9a825; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.key-box ul { margin:3px 0 0 12px; padding:0; }
.key-box li { margin:2px 0; }
.example-box { background:#f3e5f5; border-left:3px solid #7b1fa2; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.warn-box { background:#ffebee; border-left:3px solid #c62828; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.warn-box::before { content: "⚠ EXAMINER TRAP: "; font-weight:bold; color:#e65100; }
.tip-box { background:#e8f5e9; border-left:3px solid #2e7d32; padding:4px 8px; margin:4px 0; font-size:9pt; border-radius:0 4px 4px 0; }
.recall-box { background:#e8f5e9; border-left:3px solid #2e7d32; padding:4px 8px; margin:4px 0; font-size:9pt; font-weight:bold; border-radius:0 4px 4px 0; }

.mcq-box { background:#f8f9fa; border:1px solid #dee2e6; padding:6px 10px; margin:5px 0; border-radius:4px; font-size:9pt; }
.options { list-style:none; margin:4px 0 0 0; padding:0; }
.options li { padding:2px 0; }
.options li.wrong { color:#c62828; }
.options li.correct { color:#2e7d32; font-weight:bold; }
.options .why { font-size:8pt; color:#555; margin-left:8px; font-style:italic; }
.self-test-box { background:#e8eaf6; border:1px dashed #5c6bc0; padding:6px 10px; margin:6px 0; border-radius:4px; font-size:9pt; }
details summary {
  cursor:pointer; display:inline-block; margin-top:6px; padding:2px 10px;
  background:#e8eaf6; color:#3949ab; border:1px solid #9fa8da;
  border-radius:4px; font-size:8.5pt; font-weight:600; user-select:none;
  list-style:none;
}
details summary::-webkit-details-marker { display:none; }
details[open] > summary { background:#c5cae9; }
details > *:not(summary) { margin-top:6px; }

/* ── CODE ── */
pre {
  background:#f8f9fa;
  color:#212529;
  border:1px solid #dee2e6;
  border-radius:4px;
  margin:4px 0;
  padding:8px 10px;
  font-size:8.5pt;
  line-height:1.5;
  white-space:pre-wrap;
  word-break:break-word;
}
pre code {
  white-space:pre;
  word-break:normal;
  display:block;
  overflow-x:auto;
  font-size:inherit;
}
code {
  font-family:'Courier New', monospace;
  font-size:0.95em;
}
.kw { color:#0000ff; } .bi { color:#267f99; } .st { color:#a31515; }
.cm { color:#008000; } .nm { color:#098658; } .fn { color:#795e26; }
.va { color:#001080; }

/* ── TABLES ── */
table { border-collapse:collapse; width:100%; margin:5px 0; font-size:8.5pt; }
th, td { border:1px solid #bbb; padding:3px 6px; text-align:left; }
th { background:#eeeeee; font-weight:bold; color:#333; }
tr:nth-child(even) { background:#fafafa; }
.highlight-row { background:#fff9c4 !important; font-weight:bold; }

/* ── CARDS ── */
.card-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(200px,1fr)); gap:6px; margin:8px 0; }
.card { background:#fff; border:1px solid #ccc; border-radius:4px; padding:6px 8px; font-size:8.5pt; }
.card .card-title { font-weight:bold; font-size:9pt; color:#0f3460; margin-bottom:3px; border-bottom:1px solid #eee; padding-bottom:2px; }

/* ── PRIORITY TAGS ── */
.priority-tag { font-size:7.5pt; padding:1px 6px; border-radius:10px; font-weight:bold; white-space:nowrap; }
.critical { background:#fce4ec; color:#ad1457; }
.high { background:#fff3e0; color:#e65100; }
.medium { background:#fff8e1; color:#f57f17; }
.marks-badge { display:inline-block; background:#e94560; color:#fff; font-size:7.5pt; padding:1px 5px; border-radius:10px; font-weight:bold; margin-left:5px; }

/* ── TOC STICKY SIDEBAR (screen only) ── */
@media screen {
  body { display:grid; grid-template-columns:165px 1fr; gap:0; }
  .toc-sidebar { position:sticky; top:0; height:100vh; overflow-y:auto; background:#f8f9fa; padding:10px 6px; font-size:8pt; color:#333; border-right:1px solid #ddd; }
  .toc-sidebar h4 { font-size:8.5pt; color:#16213e; margin:0 0 8px; padding-bottom:4px; border-bottom:1px solid #ddd; }
  .toc-sidebar a { display:block; color:#0f3460; text-decoration:none; padding:2px 4px; border-radius:3px; margin-bottom:1px; }
  .toc-sidebar a:hover { background:#e8f4f8; }
  .toc-sidebar .toc-h3 { padding-left:10px; font-size:7.5pt; color:#555; }
  .main-content { padding:10px 14px; min-width:0; }
}
@media screen and (max-width:640px) {
  body { grid-template-columns:1fr; }
  .toc-sidebar { display:none; }
  .main-content { grid-column:1 / -1; padding:8px; }
}
@media print {
  .toc-sidebar { display:none; }
  .main-content { grid-column:1 / -1; padding:0; }
  body { display:block; }
  .print-bar { display:none; }
  .collapse-btn { display:none !important; }
  .section-body { display:block !important; }
  /* Force all <details> open and hide the toggle-button summary text */
  details { display:block !important; }
  details > *:not(summary) { display:block !important; visibility:visible !important; }
  details > summary { display:none !important; }
}

/* ── PRINT BUTTONS ── */
.print-bar { position:fixed; top:8px; right:8px; display:flex; gap:6px; z-index:999; }
.print-btn { padding:5px 14px; color:#fff; border:none; border-radius:4px; cursor:pointer; font-size:9pt; box-shadow:0 2px 6px rgba(0,0,0,0.3); }
.print-btn.color-btn { background:#e94560; }
.print-btn.bw-btn { background:#333; }
.print-btn.back-btn { background:#1976d2; display:none; }
.print-btn.read-btn { background:#2e7d32; }

/* ── READ MODE ── */
@media screen {
  body.read-mode .print-bar { display:none !important; }
  body.read-mode .toc-sidebar { display:none !important; }
  body.read-mode .main-content {
    grid-column:1 / -1; max-width:860px; margin:0 auto;
    padding:24px 32px; font-size:11pt; line-height:1.75;
  }
}
#btnExitRead {
  display:none; position:fixed; bottom:16px; right:16px;
  background:rgba(0,0,0,0.55); color:#fff; border:none; border-radius:20px;
  padding:6px 14px; font-size:9pt; cursor:pointer; z-index:9999;
}
body.read-mode #btnExitRead { display:block; }
@media print { #btnExitRead { display:none !important; } }

/* ── B&W MODE OVERRIDES ── */
body.bw-mode { background:#fff !important; color:#000 !important; }
body.bw-mode .def-box, body.bw-mode .key-box, body.bw-mode .example-box,
body.bw-mode .warn-box, body.bw-mode .tip-box, body.bw-mode .recall-box,
body.bw-mode .mcq-box, body.bw-mode .self-test-box {
  background:#fff !important; border:1px solid #ccc !important; border-left:none !important;
}
body.bw-mode h1 { color:#000 !important; border-bottom:2px solid #000 !important; }
body.bw-mode h2 { background:#fff !important; border-left:2px solid #000 !important; color:#000 !important; }
body.bw-mode h3 { color:#000 !important; border-bottom:1px solid #000 !important; }
body.bw-mode pre { background:#fff !important; color:#000 !important; border:1px solid #ccc !important; }
body.bw-mode .kw, body.bw-mode .bi, body.bw-mode .st, body.bw-mode .cm,
body.bw-mode .nm, body.bw-mode .fn, body.bw-mode .va { color:#000 !important; }
body.bw-mode table th { background:#eee !important; color:#000 !important; }
body.bw-mode tr:nth-child(even) { background:#fff !important; }
body.bw-mode .priority-tag, body.bw-mode .marks-badge { background:#fff !important; color:#000 !important; border:1px solid #000 !important; }
body.bw-mode .card { background:#fff !important; border:1px solid #ccc !important; }
body.bw-mode .highlight-row { background:#fff !important; }
body.bw-mode .toc-sidebar { background:#fff !important; border-right:1px solid #ccc !important; }
body.bw-mode .toc-sidebar a { color:#000 !important; }

/* ── COLLAPSIBLE SECTIONS ── */
.collapse-btn { float:right; background:none; border:none; cursor:pointer; font-size:10pt; color:#aaa; padding:0 4px; margin-left:6px; }
.collapse-btn:hover { color:#e94560; }
</style>
</head>
<body>

<!-- Print / mode buttons (hidden on print) -->
<div class="print-bar">
  <button class="print-btn read-btn"   id="btnReadMode" onclick="toggleReadMode()">&#128214; Read Mode</button>
  <button class="print-btn back-btn"   id="btnBackColor" onclick="backToColor()">&#127775; Back to Color</button>
  <button class="print-btn bw-btn"     id="btnPrintBW"   onclick="printBW()">&#128438; Print B&amp;W</button>
  <button class="print-btn color-btn"                    onclick="printColor()">&#128438; Print Color</button>
</div>
<button id="btnExitRead" onclick="toggleReadMode()">&#10005; Exit Read Mode</button>

<!-- JS: print modes + collapsible sections + TOC auto-build -->
<script>
function printColor() {
  document.body.classList.remove('bw-mode');
  document.getElementById('btnPrintBW').style.display='inline-block';
  document.getElementById('btnBackColor').style.display='none';
  window.print();
}
function printBW() {
  document.body.classList.add('bw-mode');
  document.getElementById('btnPrintBW').style.display='none';
  document.getElementById('btnBackColor').style.display='inline-block';
  window.print();
}
function backToColor() {
  document.body.classList.remove('bw-mode');
  document.getElementById('btnPrintBW').style.display='inline-block';
  document.getElementById('btnBackColor').style.display='none';
}
function toggleReadMode() {
  document.body.classList.toggle('read-mode');
}

// Auto-collapsible h2/h3 sections
(function(){
  function setup(){
    document.querySelectorAll('.main-content h2,.main-content h3').forEach(function(h){
      var btn=document.createElement('button');
      btn.className='collapse-btn';btn.textContent='▼';
      h.appendChild(btn);
      var wrapper=document.createElement('div');wrapper.className='section-body';
      var level=parseInt(h.tagName[1]),next=h.nextElementSibling;
      while(next){
        var tag=next.tagName||'';
        if(/^H[1-6]$/.test(tag)&&parseInt(tag[1])<=level)break;
        var after=next.nextElementSibling;wrapper.appendChild(next);next=after;
      }
      h.insertAdjacentElement('afterend',wrapper);
      btn.addEventListener('click',function(e){
        e.stopPropagation();
        var open=wrapper.style.display!=='none';
        wrapper.style.display=open?'none':'';
        btn.textContent=open?'▶':'▼';
      });
    });
    // Expand/Collapse All in TOC
    var toc=document.querySelector('.toc-sidebar');
    if(toc){
      var bar=document.createElement('div');
      bar.style.cssText='display:flex;gap:4px;margin-bottom:8px;';
      ['Expand All','Collapse All'].forEach(function(label){
        var b=document.createElement('button');
        b.textContent=label;
        b.style.cssText='flex:1;font-size:7.5pt;padding:2px 4px;border:1px solid #ccc;border-radius:3px;cursor:pointer;background:#fff;';
        b.addEventListener('click',function(){
          var expand=label==='Expand All';
          document.querySelectorAll('.section-body').forEach(function(w){w.style.display=expand?'':'none';});
          document.querySelectorAll('.collapse-btn').forEach(function(b){b.textContent=expand?'▼':'▶';});
        });
        bar.appendChild(b);
      });
      toc.insertBefore(bar,toc.firstChild);
    }
    // Auto-build TOC links from h2/h3 IDs
    if(toc){
      document.querySelectorAll('.main-content h2,.main-content h3').forEach(function(h){
        if(!h.id){h.id=h.textContent.trim().replace(/[^a-z0-9]+/gi,'-').toLowerCase().slice(0,40);}
        var a=document.createElement('a');
        a.href='#'+h.id;
        a.textContent=h.textContent.replace('▼','').replace('▶','').trim();
        if(h.tagName==='H3')a.classList.add('toc-h3');
        toc.appendChild(a);
      });
    }
  }
  if(document.readyState==='loading'){document.addEventListener('DOMContentLoaded',setup);}else{setup();}
})();

// Auto-open details when printing
(function(){
  function openDetails(){
    document.querySelectorAll('details').forEach(function(d){
      if(!d.hasAttribute('open')){d.setAttribute('data-was-closed','');d.setAttribute('open','');}
    });
    document.querySelectorAll('.section-body').forEach(function(w){
      if(w.style.display==='none'){w.setAttribute('data-was-hidden','');w.style.display='';}
    });
  }
  function restoreDetails(){
    document.querySelectorAll('[data-was-closed]').forEach(function(d){d.removeAttribute('open');d.removeAttribute('data-was-closed');});
    document.querySelectorAll('[data-was-hidden]').forEach(function(w){w.style.display='none';w.removeAttribute('data-was-hidden');});
  }
  window.addEventListener('beforeprint',openDetails);
  window.addEventListener('afterprint',restoreDetails);
})();
</script>

<!-- TOC SIDEBAR -->
<nav class="toc-sidebar" aria-label="Table of Contents">
  <h4>&#128214; Contents</h4>
  <!-- TOC links auto-built by JS above -->
</nav>

<!-- MAIN CONTENT -->
<div class="main-content">

Generate these sections in order (all inside the main-content div):

<h1 id="top">Operators, precedence and expression evaluation Theory — Lecture 3</h1>
<p style="text-align:center;color:#555;font-size:8.5pt;">CBSE | XII CS | Computational Thinking and Programming – 2 | 35 min</p>

<h2 id="s1">1. Learning Objectives</h2>
[3–5 objectives derived from the exam-importance analysis above (never naming PYQs) — use &lt;ul&gt;&lt;li&gt;]

<h2 id="s2">2. 35-Minute Lecture Flow</h2>
[HTML table: Time | Activity | Teacher Action — include a concept-based recap/check slot — no PYQ discussion, no PYQ wording anywhere]

<h2 id="s3">3. Concept Notes</h2>
[For EVERY sub-concept surfaced by the exam-frequency analysis, never naming or displaying actual board questions:
  - .def-box for definition with "In exam language: ..." line
  - .key-box with syntax/rules as &lt;ul&gt;&lt;li&gt;
  - .example-box for worked examples
  - &lt;pre&gt;&lt;code&gt; for code with .kw/.bi/.st/.cm/.nm token spans
  - .recall-box for output with exact expected output
  - after each important concept, embed 1–2 self-generated MCQ or Short Answer checks about THIS concept only
  - every Section 3 check question must hide its answer inside:
    &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;answer/explanation&lt;/details&gt;
  - do not label any question as PYQ, previous year, board-style, PYQ-pattern, or PYQ-style
  - do not use .pyq-box or .pyq-meta here (in Combined mode .pyq-box is reserved for Section 7)
]

<h2 id="s4">4. Examiner Tricks &amp; Common Mistakes</h2>
[Create one .warn-box for each trap from the EXAMINER FINGERPRINT section.
Each .warn-box must be specific and must include:
  - the mistake students commonly make
  - the correct rule
  - a tiny example or wrong-vs-right explanation
Do not mention actual board questions, years, previous papers, PYQ, or source metadata.]

<h2 id="s5">5. Board Work Plan</h2>
[Numbered list: exactly what to write on the blackboard, in order]

<h2 id="s6">6. Classroom Practice Questions</h2>
[Self-generated from the examiner-trap patterns analysed above — never call these PYQ-pattern/PYQ-style/board-style. CRITICAL: every answer MUST be inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; — never expose the answer directly.

3×1M MCQ + 5×1-2M Short Answer only.
Theory lecture restriction:
- Do NOT include actual PYQs.
- Do NOT include programming/long-answer/HOTS questions in theory lecture practice.
- Frame original MCQ/Short Answer questions from exam-frequency concepts and examiner traps only.
- Every question must map to one concept/trap discovered in Section 4.

MCQ structure:
&lt;div class="mcq-box"&gt;
  &lt;b&gt;Q1.&lt;/b&gt; Question text?&lt;br&gt;
  &lt;ul class="options"&gt;
    &lt;li&gt;a) ...&lt;/li&gt;
    &lt;li&gt;b) ...&lt;/li&gt;
    &lt;li&gt;c) ...&lt;/li&gt;
    &lt;li&gt;d) ...&lt;/li&gt;
  &lt;/ul&gt;
  &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;
    &lt;ul class="options"&gt;
      &lt;li class="wrong"&gt;a) ... — reason why wrong&lt;/li&gt;
      &lt;li class="correct"&gt;b) ... ✓ — reason why correct&lt;/li&gt;
      ...
    &lt;/ul&gt;
  &lt;/details&gt;
&lt;/div&gt;

Short-answer structure:
&lt;div class="self-test-box"&gt;&lt;b&gt;Q4.&lt;/b&gt; Question&lt;br&gt;&lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;Full answer&lt;/details&gt;&lt;/div&gt;]



<h2 id="s7">7. Student Notes (Copy-ready)</h2>
[Concise notes — every concept highlighted by the exam-frequency analysis, written purely as concept notes (no PYQ wording) — in .key-box and .def-box; self-check questions in .self-test-box with &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;answer&lt;/details&gt;]

<h2 id="s8">8. Homework</h2>
[DYNAMIC HOMEWORK — match this concept and the question types the board actually uses for it
(self-generate the questions; never label them as previous-year or board questions):
- 2×1M (MCQ / very-short answer)
- 2×2M short answer
- 1×3M short answer (or, for a coding topic, a short program / output-prediction question)
- Do NOT include 3M/5M or programming questions — this concept is not assessed that way
Dynamic rule: include a 5M long-answer or a programming question ONLY when this concept is genuinely
assessed that way; never force unsupported marks (e.g. a 5M) or question types. same concept — self-generated, never labelled as PYQ-pattern or board-style.
Mark difficulty with .critical/.high/.medium tag.
EVERY answer wrapped in &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt; inside .self-test-box or .mcq-box]

<h2 id="s9">9. Exam Tips</h2>
[5 specific tips as .tip-box — derived from examiner traps for THIS topic only — written as plain tips, no PYQ wording]

<h2 id="s10">10. Last-Minute Revision Cards</h2>
&lt;div class="card-grid"&gt;
[One .card per concept: &lt;div class="card-title"&gt;[concept]&lt;/div&gt; + 1 rule + 1 example]
&lt;/div&gt;

</div><!-- end .main-content -->
</body>
</html>

HARD OUTPUT RULES:
- Output ONLY the HTML document starting with &lt;!DOCTYPE html&gt;
- Do NOT wrap the output in markdown code fences.
- Do NOT add explanatory text before or after the HTML.
- Use ONLY content from the lecture topic ("Operators, precedence and expression evaluation").
- Do NOT include content from other topics.
- The exam-frequency input is private analysis only.
- Final visible HTML must NOT include:
    * actual board question text
    * year labels
    * section labels from papers
    * previous-paper metadata
    * the word "PYQ"
    * phrases like "previous year question", "PYQ-style", "PYQ-pattern", or "board-style"
- Every question, example, and practice item in the final HTML must be self-generated and concept-focused.
- Always finish the document completely through &lt;/html&gt;.
- If the answer becomes long, keep Section 3 complete first, then make Sections 7–10 compact instead of truncating.
- However many concepts the analysis surfaces, self-generate enough Section 3 and Section 6 checks to cover all important traps.
- Never dump real board questions to compensate for a large question pool.

ANSWER HIDING RULES:
- Section 3 concept checks: every answer must be hidden inside &lt;details&gt;&lt;summary&gt;▶ View Answer&lt;/summary&gt;...&lt;/details&gt;.
- Section 6 MCQs: options must be listed without .correct or .wrong before details.
- Section 6 MCQ answer analysis must appear only inside &lt;details&gt;.
- Section 6 short-answer questions: every answer must be hidden inside &lt;details&gt;.
- Section 7 self-check questions: every answer must be hidden inside &lt;details&gt;.
- Section 8 homework: every answer must be hidden inside &lt;details&gt;.
- The beforeprint JS already auto-opens all &lt;details&gt; for printing; never remove or skip this feature.

THEORY LECTURE STRUCTURE RULE:
- This theory lecture has no visible board-question discussion section.
- Sections 7–10 are allowed and required:
    Section 7: Student Notes
    Section 8: Homework
    Section 9: Exam Tips
    Section 10: Last-Minute Revision Cards

CODE SIZE RULE:
- Inline code must appear almost the same size as surrounding normal text.
- Do NOT use fixed 8.5pt size for all &lt;code&gt; elements.
- Use code { font-size:0.95em; } for inline code.
- Use pre { font-size:8.5pt; } for block code.
- Use pre code { font-size:inherit; } so code blocks remain compact.
- Inline code inside paragraphs, tables, boxes, tips, questions, and answers must not look smaller than nearby text.

BOX / CLASS USAGE RULES:
- Do NOT use .pyq-box or .pyq-meta in theory lectures.
- Use .mcq-box for MCQs.
- Use .self-test-box for short-answer checks and homework.
- Use .warn-box for examiner traps.
- Use .tip-box for exam tips.
- Use .def-box and .key-box for notes.
- Use .example-box for worked examples.
- Use .recall-box for exact output.

HTML TEMPLATE RULES:
- All generated content must go inside &lt;div class="main-content"&gt;.
- The &lt;nav class="toc-sidebar"&gt; is already present in the template.
- JS auto-builds TOC links from h2/h3 headings.
- Print buttons including Read Mode are already present in the template.
- Do NOT add print buttons again.
- Include the full CSS and JS exactly as given.