Primary 4 Mathematics Semestral Assessment 2 (End of Year) Paper 3

<!-- TuitionGoWhere generation metadata: stage=3-1; model=moonshotai/kimi-k2.6:free; model_label=Kimi K2.6 Free; generated=2026-06-09; Sources: Stage 2-1 real exam-derived templates and Stage 2-2 exam-enriched syllabus. -->

TuitionGoWhere Exam Practice (AI) - SA2

Mathematics Primary 4 - Whole Numbers

Version 3 of 5

---

Subject: Mathematics
Level: Primary 4
Paper: SA2 Practice Paper
Duration: 1 hour
Total Marks: 50

Name: _________________________
Class: _________________________
Date: _________________________

---

Instructions to Candidates

1. Write your name, class, and date in the spaces provided above.
2. This paper consists of THREE sections: Section A, Section B, and Section C.
3. Answer all questions.
4. Show all your working clearly. Marks will be given for correct method even if the final answer is wrong.
5. Use a calculator where appropriate.

---

Section A: Multiple Choice Questions (10 marks)

Choose the correct answer for each question and write its letter (A, B, C, or D) in the bracket provided. Each question carries 1 mark.

Questions 1–10

---

1. In the number 87,654, which digit is in the thousands place?

A) 8
B) 7
C) 6
D) 5

Answer: ( )

---

2. What does the digit 4 stand for in 94,726?

A) 400
B) 4,000
C) 40,000
D) 4

Answer: ( )

---

3. Which number is the greatest?

A) 78,099
B) 78,909
C) 78,990
D) 79,089

Answer: ( )

---

4. Round 63,749 to the nearest thousand.

A) 63,000
B) 63,700
C) 64,000
D) 63,750

Answer: ( )

---

5. Find the value of 45,000 + 8,000 − 12,500.

A) 40,500
B) 41,500
C) 50,500
D) 61,500

Answer: ( )

---

6. A number rounded to the nearest hundred is 82,600. Which of the following could be the original number?

A) 82,549
B) 82,640
C) 82,660
D) 82,699

Answer: ( )

---

7. 72,050 people attended a concert. What is 72,050 written in words?

A) Seventy-two thousand and fifty
B) Seventy-two thousand five hundred
C) Seven thousand two hundred and fifty
D) Seventy-two thousand fifty

Answer: ( )

---

8. Find the missing number: 15,000 × ___ = 150,000

A) 10
B) 100
C) 1,000
D) 10,000

Answer: ( )

---

9. A bakery packs 48 buns into boxes of 6. How many boxes are needed?

A) 6
B) 7
C) 8
D) 9

Answer: ( )

---

10. Which expression gives the same value as (24 + 36) × 5?

A) 24 + 36 × 5
B) 24 × 5 + 36
C) 24 × 5 + 36 × 5
D) 24 + 36 + 5

Answer: ( )

---

Section B: Short Answer Questions (20 marks)

Show your working clearly in the space provided. Each question carries 2 marks.

Questions 11–20

---

11. Write "seventy-four thousand and eight" in numerals.

Answer: _________________________

---

12. Arrange the following numbers from the smallest to the greatest.

47,306 | 47,603 | 47,036 | 47,630

Answer: _________________________ , _________________________ , _________________________ , _________________________

---

13. What is the smallest 5-digit number that can be formed using the digits 4, 7, 0, 2, and 9, using each digit only once?

Answer: _________________________

---

14. Round 95,438 to (a) the nearest ten: _________________________ (b) the nearest thousand: _________________________

---

15. Complete the number pattern: 12,450, 12,550, 12,650, ___, ___, 12,950

Answer: _________________________ , _________________________

---

16. A supermarket had 52,400 eggs. After selling some eggs, 38,650 eggs were left. How many eggs were sold?

Show your working.

Answer: _________________________ eggs

---

17. Mrs. Lim bought 25 boxes of chocolates. Each box contained 18 chocolates. She then gave 120 chocolates to her pupils. How many chocolates did she have left?

Show your working.

Answer: _________________________ chocolates

---

18. A factory produces 8,450 toys each day. How many toys will it produce in 15 days?

Show your working.

Answer: _________________________ toys

---

19. Tom has 456 stamps. Jerry has 3 times as many stamps as Tom. How many stamps do they have altogether?

Show your working.

Answer: _________________________ stamps

---

20. 8 identical bags of rice have a total mass of 24 kg. What is the mass of 15 such bags of rice?

Show your working.

Answer: _________________________ kg

---

Section C: Long Answer Questions (20 marks)

Show all your working clearly. Each question carries 4 marks.

Questions 21–24

---

21. The table below shows the number of visitors to a museum over four months.

<image_placeholder> id: Q21-fig1 type: table linked_question: 21 description: A table showing monthly museum visitors for four months labels: Month (Jan, Feb, Mar, Apr), Number of visitors values: January: 45,280; February: 38,650; March: 52,400; April: 41,750 must_show: All four months with visitor numbers clearly aligned; title "Museum Visitors 2025" </image_placeholder>

(a) In which month were there the most visitors?

Answer: _________________________

(b) Find the total number of visitors in January and February.

Show your working.

Answer: _________________________ visitors

(c) The museum rounded the March visitors to the nearest thousand for a newspaper report. What number was reported?

Show your working.

Answer: _________________________ visitors

---

22. A school has 3,648 pupils. 1,256 are boys and the rest are girls.

(a) How many girls are there in the school?

Show your working.

Answer: _________________________ girls

(b) The girls are divided equally into 8 houses. How many girls are in each house?

Show your working.

Answer: _________________________ girls

(c) 145 new pupils join the school. If there are now 1,380 boys, how many of the new pupils are girls?

Show your working.

Answer: _________________________ girls

---

23. A fruit seller had 12,800 apples. He packed them into bags of 25.

(a) How many complete bags could he make?

Show your working.

Answer: _________________________ bags

(b) How many apples were left over?

Show your working.

Answer: _________________________ apples

(c) He sold each bag for $18. How much money did he receive from selling all the complete bags?

Show your working.

Answer: $ _________________________

---

24. <image_placeholder> id: Q24-fig1 type: diagram linked_question: 24 description: A bar model diagram showing three quantities with relationships between them labels: Unit A (Longest bar), Unit B (Middle bar, 3 parts), Unit C (Shortest bar, 1 part); bracket showing A + B = 84,600; bracket showing A is 5 times C values: A = 5 units, B = 3 units, C = 1 unit; total of A and B = 84,600 must_show: Three horizontal bars of different lengths with clear unit labels; brackets with totals; clear visual proportionality between bars </image_placeholder>

Study the bar model above.

(a) How many units represent A and B together?

Answer: _________________________ units

(b) Find the value of 1 unit.

Show your working.

Answer: _________________________

(c) Find the value of A.

Show your working.

Answer: _________________________

(d) How much greater is A than C?

Show your working.

Answer: _________________________

---

END OF PAPER

---

Mark Summary

Section	Marks
A	10
B	20
C	20
Total	50

<!-- TuitionGoWhere generation metadata: stage=3-1; model=moonshotai/kimi-k2.6:free; model_label=Kimi K2.6 Free; generated=2026-06-09; Sources: Stage 2-1 real exam-derived templates and Stage 2-2 exam-enriched syllabus. -->

TuitionGoWhere Exam Practice (AI) - SA2

Mathematics Primary 4 - Whole Numbers

Version 3 of 5 — Answer Key

---

Section A: Multiple Choice Questions (10 marks)

Question 1 (1 mark)

Answer: B) 7

Working/Explanation:

To find which digit is in the thousands place, we use a place value table:

Ten Thousands	Thousands	Hundreds	Tens	Ones
8	7	6	5	4

• The thousands place is the third position from the right (or second from the left in a 5-digit number).
• In 87,654, the digit 7 is in the thousands place.
• Common mistake: Confusing "thousands" with "thousands place" — the digit 8 stands for 80,000 (eight ten thousands), not eight thousands.

---

Question 2 (1 mark)

Answer: B) 4,000

Working/Explanation:

Place value analysis of 94,726:

Ten Thousands	Thousands	Hundreds	Tens	Ones
9	4	7	2	6

• The digit 4 is in the thousands place.
• Therefore, the digit 4 stands for: 4 × 1,000 = 4,000
• Key concept: "Stand for" asks for the value of the digit, not just its position. Many students answer "4 thousands" which is acceptable wording, but the numerical value is 4,000.

---

Question 3 (1 mark)

Answer: D) 79,089

Working/Explanation:

Compare digit by digit from the left (highest place value):

Number	Ten Thousands	Thousands	Hundreds	Tens	Ones
78,099	7	8	0	9	9
78,909	7	8	9	0	9
78,990	7	8	9	9	0
79,089	7	9	0	8	9

• All numbers have 7 ten thousands.
• Comparing thousands: 78,099 and 78,909/78,990 have 8 thousands; 79,089 has 9 thousands.
• Therefore 79,089 is the greatest.
• Method: When comparing whole numbers, always start from the leftmost digit and move right until you find a difference.

---

Question 4 (1 mark)

Answer: C) 64,000

Working/Explanation:

Rounding 63,749 to the nearest thousand:

1. Identify the thousands digit: 3 (in 63,749)
2. Look at the digit to its right (hundreds digit): 7
3. Rule: If this digit is 5 or more, round the thousands digit up.
4. Since 7 ≥ 5, round 3 up to 4.
5. Change all digits to the right to zeros: 64,000

• Common mistake: Some students look at the 4 (tens digit) instead of the 7 (hundreds digit). Always look at the digit immediately to the right of your target place value.

---

Question 5 (1 mark)

Answer: A) 40,500

Working/Explanation:

Follow order of operations (left to right for addition and subtraction):

$45,000 + 8,000 - 12,500$ $= 53,000 - 12,500$ $= \boxed{40,500}$

• Verification: 40,500 + 12,500 = 53,000 ✓ and 53,000 − 8,000 = 45,000 ✓

---

Question 6 (1 mark)

Answer: B) 82,640

Working/Explanation:

For a number to round to 82,600 when rounded to the nearest hundred:

• The hundreds digit must be 6 (so we're rounding to 82,600)
• The tens digit must be 0–4 (round down) or 5–9 (round up to 82,700)

Wait — let me re-analyze. 82,600 as a rounded value means:

• If rounding down: original number is 82,600 to 82,649 (tens digit 0–4, keep 600)
• If rounding up: original number is 82,550 to 82,599 (tens digit 5–9, round 550 up to 600)

So possible range: 82,550 to 82,649

Checking options:

• A) 82,549 → rounds to 82,500 (tens digit 4, so round down: 82,500) ✗
• B) 82,640 → tens digit is 4, so round down: 82,600 ✓
• C) 82,660 → tens digit is 6, so round up: 82,700 ✗
• D) 82,699 → tens digit is 9, so round up: 82,700 ✗

Answer: B

---

Question 7 (1 mark)

Answer: A) Seventy-two thousand and fifty

Working/Explanation:

Break down 72,050 using place value:

Ten Thousands	Thousands	Hundreds	Tens	Ones
7	2	0	5	0

• 72,050 = 70,000 + 2,000 + 50 = seventy-two thousand + fifty
• Since there are no hundreds, we say "seventy-two thousand and fifty"
• Singapore convention: We include "and" before the last part when there are gaps (no hundreds here).

Option	Analysis
A	Correct: "Seventy-two thousand and fifty"
B	Wrong: says "five hundred" instead of "fifty"
C	Wrong: completely wrong magnitude
D	Wrong: missing "and" before fifty

---

Question 8 (1 mark)

Answer: A) 10

Working/Explanation:

$15,000 \times \_\_\_ = 150,000$

To find the missing multiplier: $\text{Missing number} = 150,000 \div 15,000 = \frac{150,000}{15,000} = \frac{150}{15} = \boxed{10}$

• Shortcut: Count zeros — 150,000 has one more zero than 15,000, so multiply by 10.
• Concept: 15,000 × 10 = 15,000 × (10 ones) = 150,000

---

Question 9 (1 mark)

Answer: C) 8

Working/Explanation:

This is a division problem: $\text{Number of boxes} = 48 \div 6 = \boxed{8}$

• Interpretation: We need 8 groups of 6 buns to make 48 buns total.
• Verification: 8 × 6 = 48 ✓

---

Question 10 (1 mark)

Answer: C) 24 × 5 + 36 × 5

Working/Explanation:

This tests the distributive property: $(a + b) \times c = a \times c + b \times c$

$(24 + 36) \times 5 = 24 \times 5 + 36 \times 5 = 60 \times 5 = 300$

Checking options:

Option	Value	Correct?
A) 24 + 36 × 5	24 + 180 = 204	✗ (wrong order of operations)
B) 24 × 5 + 36	120 + 36 = 156	✗
C) 24 × 5 + 36 × 5	120 + 180 = 300	✓
D) 24 + 36 + 5	65	✗

---

Section B: Short Answer Questions (20 marks)

Question 11 (2 marks)

Answer: 74,008

Working/Explanation:

Break down "seventy-four thousand and eight":

• "Seventy-four thousand" = 74,000
• "and eight" = 8 (no hundreds, no tens, just 8 ones)
• Total: 74,000 + 8 = 74,008

Place Value	Digit
Ten Thousands	7
Thousands	4
Hundreds	0
Tens	0
Ones	8

• Common mistake: Writing 74,800 (swapping the 8 into hundreds place) or 74,080 (putting 8 in tens place). The word "and" signals we need to be careful about which place gets the last mentioned value.

---

Question 12 (2 marks)

Answer: 47,036, 47,306, 47,603, 47,630

Working/Explanation:

All numbers have the same ten thousands (4) and thousands (7). Compare from the left:

Number	Hundreds	Tens	Ones
47,306	3	0	6
47,603	6	0	3
47,036	0	3	6
47,630	6	3	0

Step-by-step ordering:

1. 47,036 — smallest (0 hundreds)
2. 47,306 — next (3 hundreds, 0 tens... wait, let me re-check)

Actually, correct comparison:

• 47,036: hundreds digit is 0 → smallest ✓
• 47,306: hundreds digit is 3 → second smallest
• 47,603 vs 47,630: both have 6 hundreds, so compare tens: 0 vs 3

Order: 47,036 < 47,306 < 47,603 < 47,630

• Method: When digits match from the left, keep moving right until you find a difference.

---

Question 13 (2 marks)

Answer: 20,479

Working/Explanation:

To form the smallest 5-digit number using digits 4, 7, 0, 2, 9:

Critical rule: A 5-digit number cannot start with 0.

1. Choose the smallest non-zero digit for ten thousands place: 2
2. Arrange remaining digits (4, 7, 0, 9) in ascending order for the rest: 0, 4, 7, 9

Result: 20,479

Position	Digit	Reasoning
Ten Thousands	2	Smallest non-zero available
Thousands	0	Smallest remaining
Hundreds	4	Next smallest
Tens	7	Next smallest
Ones	9	Largest remaining

• Common mistake: 04,279 = 4,279 is a 4-digit number, not valid!

---

Question 14 (2 marks)

(a) Answer: 95,440 (1 mark)

(b) Answer: 95,000 (1 mark)

Working/Explanation:

(a) Rounding to nearest ten:

• Tens digit: 3, ones digit: 8
• Look at ones digit: 8 ≥ 5, so round tens digit up from 3 to 4
• Result: 95,440

(b) Rounding to nearest thousand:

• Thousands digit: 5, hundreds digit: 4
• Look at hundreds digit: 4 < 5, so keep thousands digit as 5
• Result: 95,000

Place Value	Original	Round to Ten	Round to Thousand
Number	95,438	95,440	95,000
Key digit	ones=8	tens=3, ones=8	thousands=5, hundreds=4
Decision	—	round up	round down

---

Question 15 (2 marks)

Answer: 12,750, 12,850

Working/Explanation:

Find the pattern:

• 12,550 − 12,450 = 100
• 12,650 − 12,550 = 100

The pattern increases by 100 each time.

Continuing:

• 12,650 + 100 = 12,750

• 12,750 + 100 = 12,850

• Verify: 12,850 + 100 = 12,950 ✓

• Method: First identify the constant difference (common difference), then apply it repeatedly.

---

Question 16 (2 marks)

Answer: 13,750 eggs

Working/Explanation:

This is a subtraction problem: eggs sold = eggs at start − eggs left

$\text{Eggs sold} = 52,400 - 38,650$

Step-by-step:

  52,400
- 38,650
---------

• Ones: 0 − 0 = 0
• Tens: 0 − 5, need to borrow: 10 − 5 = 5
• Hundreds: (3 after borrow) − 6, need to borrow: 13 − 6 = 7
• Thousands: (1 after borrow) − 8, need to borrow: 11 − 8 = 3
• Ten Thousands: (4 after borrow) − 3 = 1

Result: 13,750

Verification: 38,650 + 13,750 = 52,400 ✓

---

Question 17 (2 marks)

Answer: 330 chocolates

Working/Explanation:

This is a two-step problem (multiplication then subtraction):

Step 1: Find total chocolates bought $25 \times 18 = 450 \text{ chocolates}$

Step 2: Find chocolates left after giving away $450 - 120 = \boxed{330 \text{ chocolates}}$

Alternative working: $25 \times 18 - 120 = 450 - 120 = 330$

• Common mistake: Adding 120 instead of subtracting, or calculating 25 + 18 instead of multiplying.

---

Question 18 (2 marks)

Answer: 126,750 toys

Working/Explanation:

This is multiplication: daily production × number of days

$8,450 \times 15$

Break down using distributive property: $8,450 \times 15 = 8,450 \times (10 + 5)$ $= 8,450 \times 10 + 8,450 \times 5$ $= 84,500 + 42,250$ $= \boxed{126,750}$

Standard multiplication:

   8,450
 ×    15
 -------
  42,250  (8,450 × 5)
 84,500   (8,450 × 10, shifted left)
 -------
 126,750

---

Question 19 (2 marks)

Answer: 1,824 stamps

Working/Explanation:

This is a two-step problem with the concept of "times as many":

Step 1: Find Jerry's stamps $\text{Jerry} = 3 \times 456 = 1,368 \text{ stamps}$

Step 2: Find total stamps $\text{Total} = 456 + 1,368 = \boxed{1,824 \text{ stamps}}$

Alternative: $\text{Total} = 456 + 3 \times 456 = 4 \times 456 = 1,824$

• Common mistake: Forgetting to add Tom's stamps and only giving Jerry's amount (1,368). The question asks for "altogether."

---

Question 20 (2 marks)

Answer: 45 kg

Working/Explanation:

This is a unit-rate problem (two steps: find one unit, then find total):

Step 1: Find mass of 1 bag $\text{1 bag} = 24 \div 8 = 3 \text{ kg}$

Step 2: Find mass of 15 bags $\text{15 bags} = 3 \times 15 = \boxed{45 \text{ kg}}$

Alternative (ratio method): $\frac{15}{8} \times 24 = 15 \times 3 = 45 \text{ kg}$

• Verification: 15 bags × 3 kg/bag = 45 kg, and 8 bags × 3 kg = 24 kg ✓

---

Section C: Long Answer Questions (20 marks)

Question 21 (4 marks)

Visual reference expected: Table with four months of visitor data: January 45,280; February 38,650; March 52,400; April 41,750

(a) Answer: March (1 mark)

Working/Explanation:

Compare all four values:

• January: 45,280
• February: 38,650 (smallest)
• March: 52,400 (largest)
• April: 41,750

March has 52,400 visitors, which is greater than all other months.

---

(b) Answer: 83,930 visitors (1 mark)

Working/Explanation:

$\text{Total} = 45,280 + 38,650 = \boxed{83,930}$

Step-by-step addition:

  45,280
+ 38,650
--------
  83,930

• Ones: 0 + 0 = 0
• Tens: 8 + 5 = 13, write 3, carry 1
• Hundreds: 2 + 6 + 1 = 9
• Thousands: 5 + 8 = 13, write 3, carry 1
• Ten Thousands: 4 + 3 + 1 = 8

---

(c) Answer: 52,000 visitors (2 marks)

Working/Explanation:

Rounding 52,400 to the nearest thousand:

1. Thousands digit: 2
2. Hundreds digit to the right: 4
3. Since 4 < 5, we round down (keep the thousands digit as 2)
4. Change remaining digits to zeros: 52,000

$\boxed{52,400 \approx 52,000 \text{ (to the nearest thousand)}}$

• Marking: 1 mark for correct method (identifying 4 < 5), 1 mark for correct answer.

---

Question 22 (4 marks)

(a) Answer: 2,392 girls (1 mark)

Working/Explanation:

$\text{Girls} = 3,648 - 1,256 = \boxed{2,392}$

  3,648
- 1,256
-------
  2,392

---

(b) Answer: 299 girls (1 mark)

Working/Explanation:

$\text{Girls per house} = 2,392 \div 8 = \boxed{299}$

Division working:

     299
   _____
8 | 2,392
    2 4        (8 × 300 = 2,400, too big; 8 × 200 = 1,600... let's do properly)

Step-by-step:

• 23 ÷ 8 = 2 remainder 7 (8 × 2 = 16)
• 79 ÷ 8 = 9 remainder 7 (8 × 9 = 72)
• 72 ÷ 8 = 9 (8 × 9 = 72)

Answer: 299

Verification: 299 × 8 = 2,392 ✓

---

(c) Answer: 123 girls (2 marks)

Working/Explanation:

Step 1: Find total new pupils who are girls $\text{New girls} = 3,648 + 145 - 1,380 - 2,392$

Alternatively, simpler approach:

• New total pupils: 3,648 + 145 = 3,793
• New number of boys: 1,380
• New total girls: 3,793 − 1,380 = 2,413

Step 2: Find how many new girls joined $\text{New girls who joined} = 2,413 - 2,392 = \boxed{21}$

Wait — let me recheck. The question says 145 new pupils join, and there are NOW 1,380 boys.

Original: 1,256 boys, 2,392 girls Now: ? boys, ? girls

Actually: New boys = 1,380 − 1,256 = 124 So new girls = 145 − 124 = 21

Answer: 21 girls

Marking: 1 mark for finding new boys = 124, 1 mark for finding new girls = 21.

---

Question 23 (4 marks)

(a) Answer: 512 bags (1 mark)

Working/Explanation:

$\text{Complete bags} = 12,800 \div 25 = 512$

Working: $12,800 \div 25 = 12,800 \div 100 \times 4 = 128 \times 4 = 512$

Or direct division: 12,800 ÷ 25 = 512 exactly.

Verification: 512 × 25 = 12,800 ✓

---

(b) Answer: 0 apples (1 mark)

Working/Explanation:

Since 12,800 ÷ 25 = 512 exactly with no remainder:

$\text{Left over} = 12,800 - (512 \times 25) = 12,800 - 12,800 = \boxed{0}$

---

(c) Answer: $9,216 (2 marks)

Working/Explanation:

$\text{Money} = 512 \times \$18$

Working:

   512
 ×  18
------
  4,096  (512 × 8)
  5,120  (512 × 10)
------
  9,216

$\boxed{\$9,216}$

Marking: 1 mark for correct multiplication working, 1 mark for final answer with correct unit ($).

---

Question 24 (4 marks)

Visual reference expected: Bar model showing A = 5 units, B = 3 units, C = 1 unit, with A + B = 84,600

(a) Answer: 8 units (1 mark)

Working/Explanation:

From the bar model: A = 5 units, B = 3 units

$\text{Total units for A and B} = 5 + 3 = \boxed{8 \text{ units}}$

---

(b) Answer: 10,575 (1 mark)

Working/Explanation:

Given: 8 units = 84,600

$\text{1 unit} = 84,600 \div 8 = \boxed{10,575}$

Working: $84,600 \div 8 = 10,575$

Verification: 10,575 × 8 = 84,600 ✓

---

(c) Answer: 52,875 (1 mark)

Working/Explanation:

$\text{A} = 5 \times 10,575 = \boxed{52,875}$

Working: $10,575 \times 5 = 52,875$

---

(d) Answer: 42,300 (1 mark)

Working/Explanation:

$\text{A} - \text{C} = 52,875 - 10,575 = \boxed{42,300}$

Or using units: A − C = 5 units − 1 unit = 4 units = 4 × 10,575 = 42,300

• Concept check: The bar model uses "units" as a common measure. Always convert the given total to "per unit" first, then find any quantity needed.

---

Mark Allocation Summary

Section	Question Range	Marks Per Question	Subtotal
A	1–10	1	10
B	11–20	2	20
C	21–24	4 each (with parts)	20
Total			50

---

Common Errors and Teaching Notes

Error Type	Where It Appears	Prevention Strategy
Confusing "digit" and "place value"	Q1, Q2	Emphasize: position vs. value
Rounding to wrong place value	Q4, Q14, Q21(c)	Always identify target digit first, then look immediately right
Forgetting "0" in number words	Q11	Use place value table; check every position
Not starting with smallest non-zero digit	Q13	Stress: 5-digit number cannot begin with 0
Two-step problem confusion	Q16–20	Underline what the final answer should represent
"Altogether" vs. "how many more"	Q19	Highlight keywords before calculating
Unit rate: dividing vs. multiplying	Q20	First step always "find one unit"
Bar model: not converting to unit value first	Q24	Drill: "Given total → find 1 unit → find answer"