Primary 1 Mathematics Money Quiz

Primary 1 Mathematics Quiz - Money — Answer Key

Topic: Money (Singapore currency — coins and notes) Source basis: Syllabus-aligned, AI-inferred from the 2021 MOE Singapore Primary Mathematics Syllabus (P1–P6). This answer key is not derived from past-year papers. Total marks: 25

Teaching note for students new to money:

• Coins in Singapore are written with the symbol ¢ (cents): 5¢, 10¢, 20¢, 50¢ and $1.
• Notes are written with the symbol **$** (dollars):$2, $5,$10.
• **100¢ = $1.** When you count many small coins, it is faster to change 100¢ into$1.
• To add, start with the largest amount and count on; to subtract, take away the smaller amount from the larger amount.

Section A — Recognising and counting money (1 mark each)

Question 1 — Coins: 5¢ + 10¢ + 20¢ + 50¢

Step-by-step:

1. Identify each coin: 5¢, 10¢, 20¢, 50¢.
2. Add the ones first or add by tens: 5 + 10 = 15; 15 + 20 = 35; 35 + 50 = 85. Final answer: 85¢ Mark: 1 mark for 85¢. Common mistake: Forgetting to write the unit "¢".

Question 2 — Coins: 20¢ + 20¢ + 10¢

Step-by-step:

1. Add the two 20¢ coins first: 20 + 20 = 40¢.
2. Add the 10¢ coin: 40 + 10 = 50¢. Final answer: 50¢ Mark: 1 mark for 50¢. Common mistake: Counting only two coins instead of three.

Question 3 — Coins: 50¢ + 50¢ + 5¢ + 5¢

Step-by-step:

1. 50 + 50 = 100¢.
2. 5 + 5 = 10¢.
3. 100 + 10 = 110¢. Change 100¢ into $1:$1 and 10¢ left over. Final answer: $1 and 10¢ **Mark:** 1 mark for$1 and 10¢ (accept 110¢ only if the child has not been taught the 100¢ = $1 conversion yet; in this quiz, both are acceptable but the unit must be correct). **Common mistake:** Writing 110¢ without converting to$1.

Question 4 — Coins: 5¢ + 10¢ + 20¢ + 20¢ + 5¢

Step-by-step:

1. 5 + 5 = 10¢.
2. 10 + 10 = 20¢.
3. 20 + 20 = 40¢.
4. 20 + 40 = 60¢. Final answer: 60¢ Mark: 1 mark for 60¢. Common mistake: Counting coins twice or missing the second 20¢ coin.

Question 5 — Notes: $2 +$5 + $2

Step-by-step:

1. $2 +$2 = $4.
2. $4 +$5 = $9. **Final answer:**$9 Mark: 1 mark for $9. **Common mistake:** Forgetting to write the "$" symbol.

Question 6 — Notes: $5 +$10 + $5

Step-by-step:

1. $5 +$5 = $10.
2. $10 +$10 = $20. **Final answer:**$20 Mark: 1 mark for $20. **Common mistake:** Adding the middle note twice instead of the two$5 notes.

Question 7 — Mixed: $2 + 20¢ + 10¢

Step-by-step:

1. Count the coins: 20¢ + 10¢ = 30¢.
2. Combine with the note: $2 and 30¢. **Final answer:**$2 and 30¢ Mark: 1 mark for "$2 and 30¢" (accept$2.30 only if the child is comfortable with decimal notation, but P1 should use $and ¢ separately). **Common mistake:** Writing$2.30 or just "2.30" without the symbols.

Section B — Adding and subtracting money (2 marks each)

Question 8 — Siti: 35¢ + 20¢ = ?

Concept: "Finds more" means we add. Step-by-step:

1. 35 + 20 = 55. Number sentence: 35 + 20 = 55 Final answer: 55¢ Marks: 1 mark for number sentence, 1 mark for 55¢. Common mistake: Using subtraction instead of addition because of the word "finds".

Question 9 — Ben: 80¢ − 30¢ = ?

Concept: "Spends" means we subtract. Step-by-step:

1. 80 − 30 = 50. Number sentence: 80 − 30 = 50 Final answer: 50¢ Marks: 1 mark for number sentence, 1 mark for 50¢. Common mistake: Adding instead of subtracting.

Question 10 — Mei: $4 +$5 = ?

Concept: "Gives her more" means we add dollars. Step-by-step:

1. 4 + 5 = 9. Number sentence: 4 + 5 = 9 Final answer: $9 **Marks:** 1 mark for number sentence, 1 mark for$9. Common mistake: Writing "9 dollars" without the "$" symbol.

Question 11 — Change from $1 for a 60¢ pencil

Concept: Change = money given − cost. Step-by-step:

1. Convert: $1 = 100¢.
2. 100 − 60 = 40. Working: 100 − 60 = 40 Final answer: 40¢ Marks: 1 mark for working, 1 mark for 40¢. Common mistake: Forgetting to change $1 into 100¢ before subtracting.

Question 12 — 90¢ shared equally by 3 friends

Concept: "Share equally" means division; each friend gets the same amount. Step-by-step:

1. 90 ÷ 3 = 30. (3 × 30 = 90) Number sentence: 90 ÷ 3 = 30 Final answer: 30¢ Marks: 1 mark for number sentence, 1 mark for 30¢. Common mistake: Using multiplication instead of division.

Question 13 — 2 ice-creams at 25¢ each

Concept: "Each" and "altogether" mean multiplication as repeated addition: 25 + 25. Step-by-step:

1. 2 × 25 = 50. Number sentence: 2 × 25 = 50 Final answer: 50¢ Marks: 1 mark for number sentence, 1 mark for 50¢. Common mistake: Writing 2 + 25 = 27 instead of multiplication.

Section C — Mixed money problems (2 marks each)

Question 14 — Compare Bank A and Bank B

Visual check: Bank A has 4 × 20¢ = 80¢. Bank B has 3 × 50¢ = 150¢. Step-by-step:

1. Bank A: 4 × 20 = 80¢.
2. Bank B: 3 × 50 = 150¢.
3. Difference: 150 − 80 = 70¢. Final answers: Bank B has more money. Difference: 70¢. Marks: 1 mark for "Bank B"; 1 mark for 70¢. Common mistake: Reading the number of coins instead of the value of the coins (4 coins vs 3 coins).

Question 15 — Does Tom have enough money?

Step-by-step:

1. Tom's money: $5 +$2 = $7.
2. Cost of book: $7.
3. $7 =$7, so he has exactly enough. Final answers:

• Tom's money: $7
• Cost of book: $7
• Tom has enough money. Marks: 1 mark for correct comparison; 1 mark for stating "has" and showing $7 =$7. Common mistake: Saying "does not have enough" because the amounts are the same.

Question 16 — Ruler 30¢ + Eraser 25¢

Visual check: ruler 30¢, eraser 25¢. Step-by-step:

1. 30 + 25 = 55. Number sentence: 30 + 25 = 55 Final answer: 55¢ Marks: 1 mark for number sentence, 1 mark for 55¢. Common mistake: Picking the sharpener's price instead of the eraser's price.

Question 17 — Change from $1 for 55¢

Visual check: total cost from Q16 is 55¢. Step-by-step:

1. $1 = 100¢.
2. 100 − 55 = 45. Working: 100 − 55 = 45 Final answer: 45¢ Marks: 1 mark for working, 1 mark for 45¢. Common mistake: Subtracting 55 from 10 instead of 100.

Question 18 — Aunty Rose's change

Step-by-step:

1. Total money: 3 × $10 =$30.
2. Change: $30 −$25 = $5. Final answers:

• Step 1: 3 × $10 =$30
• Step 2: $30 −$25 = $5
• Answer: $5 **Marks:** 1 mark for step 1; 1 mark for step 2 and the final$5. Common mistake: Writing $30 −$25 = $15 (subtracting tens incorrectly).

Question 19 — Most popular drink

Visual check: Milk 4, Juice 7, Tea 3, Water 5. The highest stack is Juice. Step-by-step:

1. Compare the four heights: 4, 7, 3, 5. The greatest is 7. Final answers: Most popular drink: Juice. Number of pupils: 7. Marks: 1 mark for "Juice"; 1 mark for 7. Common mistake: Reading "Water" because 5 is the second largest.

Question 20 — Total of Juice and Water

Visual check: Juice 7, Water 5. Step-by-step:

1. 7 + 5 = 12. Number sentence: 7 + 5 = 12 Final answer: 12 pupils Marks: 1 mark for number sentence, 1 mark for 12. Common mistake: Using subtraction instead of addition because the question says "total".