Primary 5 Mathematics Money Quiz

Primary 5 Mathematics Quiz - Money (Answer Key)

Total Marks: 50

Section A: Multiple-Choice Questions (5 × 2 marks = 10 marks)

1. Answer: (A) $33.75

• Working:
  • Total spent = $32.50 +$18.75 = $51.25
  • Money left = $85 -$51.25 = $33.75
• Teaching Note: This is a two-step problem. First, find the total amount spent by adding the cost of the book and the meal. Then, subtract the total spent from the initial amount to find the remaining money.
• Marking: 1 mark for correct total spent, 1 mark for correct final answer.

2. Answer: (C) $36

• Working:
  • Discount = 20% of $45 =$\frac{20}{100} \times 45 = $9$
  • Sale price = $45 -$9 = $36
• Teaching Note: To find a percentage of a quantity, convert the percentage to a fraction or decimal and multiply. Here, 20% = 0.2, so the discount is 0.2 × $45 =$9. Subtract the discount from the original price.
• Marking: 1 mark for correct discount, 1 mark for correct sale price.

3. Answer: (C) $20.00

• Working:
  • Cost of 1 pen = $12.50 ÷ 5 =$2.50
  • Cost of 8 pens = $2.50 × 8 =$20.00
• Teaching Note: This is a rate problem. First, find the unit price (cost of one pen) by dividing the total cost by the number of pens. Then, multiply the unit price by the new quantity.
• Marking: 1 mark for correct unit price, 1 mark for correct final answer.

4. Answer: (B) $3.40

• Working:
  • Cost of 4 pencils = $0.85 × 4 =$3.40
• Teaching Note: This is a direct multiplication problem. Multiply the cost of one pencil by the number of pencils.
• Marking: 1 mark for correct multiplication, 1 mark for correct final answer.

5. Answer: (B) $6

• Working:
  • Total spent = $28.90 +$15.50 = $44.40
  • Change = $50 -$44.40 = $5.60
  • Rounded to the nearest dollar = $6
• Teaching Note: First, add the costs of the items. Then, subtract from the amount paid. Finally, round the change to the nearest dollar. Since $5.60 is closer to$6 than to $5, we round up.
• Marking: 1 mark for correct change, 1 mark for correct rounding.

Section B: Short-Answer Questions (10 × 2 marks = 20 marks)

6. Answer: $39.55

• Working:
  • Cost of 2 boxes of chocolates = $12.80 × 2 =$25.60
  • Cost of 3 packets of biscuits = $4.65 × 3 =$13.95
  • Total cost = $25.60 +$13.95 = $39.55
• Teaching Note: Break the problem into parts. Calculate the cost of each type of item separately, then add them together.
• Marking: 1 mark for correct calculation of both item costs, 1 mark for correct total.

7. Answer: $7

• Working:
  • Profit = Selling Price - Cost Price = $25 -$18 = $7
• Teaching Note: Profit is the difference between the selling price and the cost price. If the selling price is higher, it's a profit.
• Marking: 1 mark for correct formula, 1 mark for correct answer.

8. Answer: $33

• Working:
  • Cost of 2 children's tickets = $9.50 × 2 =$19
  • Cost of 1 adult ticket = $14
  • Total cost = $19 +$14 = $33
• Teaching Note: Calculate the cost of each type of ticket separately, then add them together.
• Marking: 1 mark for correct calculation of children's tickets, 1 mark for correct total.

9. Answer: $1.80

• Working:
  • Cost of 6 individual bottles = $3.20 × 6 =$19.20
  • Savings = $19.20 -$17.40 = $1.80
• Teaching Note: First, find the total cost of buying the bottles individually. Then, subtract the pack price from this total to find the savings.
• Marking: 1 mark for correct individual cost, 1 mark for correct savings.

10. Answer: $102

• Working:
  • Discount = 15% of $120 =$\frac{15}{100} \times 120 = $18$
  • Price after discount = $120 -$18 = $102
• Teaching Note: To find a percentage of a quantity, convert the percentage to a fraction or decimal and multiply. Here, 15% = 0.15, so the discount is 0.15 × $120 =$18. Subtract the discount from the original price.
• Marking: 1 mark for correct discount, 1 mark for correct final price.

11. Answer: $45

• Working:
  • Amount spent on shoes = \frac{2}{5} \times 75 = \30$
  • Money left = $75 -$30 = $45
• Teaching Note: To find a fraction of a quantity, divide the quantity by the denominator and multiply by the numerator. Here, $\frac{2}{5}$ of $75 is (75 ÷ 5) × 2 =$30. Then, subtract from the original amount.
• Marking: 1 mark for correct amount spent, 1 mark for correct remaining amount.

12. Answer: $12.50

• Working:
  • Cost of 1 kg of rice = $7.50 ÷ 3 =$2.50
  • Cost of 5 kg of rice = $2.50 × 5 =$12.50
• Teaching Note: This is a rate problem. First, find the unit price (cost per kg) by dividing the total cost by the quantity. Then, multiply the unit price by the new quantity.
• Marking: 1 mark for correct unit price, 1 mark for correct final answer.

13. Answer: $11.45

• Working:
  • Cost of notebook = $6.90 -$2.35 = $4.55
  • Total cost = $6.90 +$4.55 = $11.45
• Teaching Note: First, find the cost of the notebook by subtracting the difference from the pencil case price. Then, add the two costs together.
• Marking: 1 mark for correct notebook price, 1 mark for correct total.

14. Answer: $18

• Working:
  • Change = $50 -$32 = $18
• Teaching Note: Change is the difference between the amount paid and the cost of the item.
• Marking: 1 mark for correct subtraction, 1 mark for correct answer.

15. Answer: $18

• Working:
  • Value of $1 coins = 12 ×$1 = $12
  • Value of 50-cent coins = 8 × $0.50 =$4
  • Value of 20-cent coins = 10 × $0.20 =$2
  • Total value = $12 +$4 + $2 =$18
• Teaching Note: Convert all values to dollars first. Remember that 50 cents = $0.50 and 20 cents =$0.20. Then, add all the values together.
• Marking: 1 mark for correct calculation of all coin values, 1 mark for correct total.

Section C: Problem-Solving Questions (5 × 4 marks = 20 marks)

16. Answer: $31

• Working:
  • Step 1: Discount = 20% of $45 =$\frac{20}{100} \times 45 = $9$
  • Step 2: Sale price = $45 -$9 = $36
  • Step 3: Final price = $36 -$5 = $31
• Teaching Note: This is a multi-step problem. First, calculate the discount and the sale price. Then, apply the voucher discount to the sale price.
• Marking:
  • 1 mark for correct discount
  • 1 mark for correct sale price
  • 1 mark for correct final price
  • 1 mark for correct final answer with units

17. Answer: $6

• Working:
  • Step 1: Total selling price = 20 × $0.80 =$16
  • Step 2: Profit = $16 -$10 = $6
• Teaching Note: First, find the total revenue from selling all the apples. Then, subtract the cost price from the revenue to find the profit.
• Marking:
  • 1 mark for correct total selling price
  • 1 mark for correct profit
  • 1 mark for correct working shown
  • 1 mark for correct final answer with units

18. Answer: $23

• Working:
  • Step 1: Discount = 25% of $36 =$\frac{25}{100} \times 36 = $9$
  • Step 2: Sale price = $36 -$9 = $27
  • Step 3: Change = $50 -$27 = $23
• Teaching Note: This is a multi-step problem. First, calculate the discount and the sale price. Then, subtract the sale price from the amount paid to find the change.
• Marking:
  • 1 mark for correct discount
  • 1 mark for correct sale price
  • 1 mark for correct change
  • 1 mark for correct final answer with units

19. Answer: $74.80

• Working:
  • Step 1: Discount = 15% of $80 =$\frac{15}{100} \times 80 = $12$
  • Step 2: Sale price = $80 -$12 = $68
  • Step 3: Increase = 10% of $68 =$\frac{10}{100} \times 68 = $6.80$
  • Step 4: Final price = $68 +$6.80 = $74.80
• Teaching Note: This is a multi-step problem. First, calculate the discount and the sale price. Then, calculate the increase based on the sale price (not the original price). Finally, add the increase to the sale price.
• Marking:
  • 1 mark for correct discount
  • 1 mark for correct sale price
  • 1 mark for correct increase
  • 1 mark for correct final price

20. Answer: $0.50

• Working:
  • Step 1: Cost of 3 sets = $6.50 × 3 =$19.50
  • Step 2: Change = $20 -$19.50 = $0.50
• Teaching Note: First, find the total cost of the 3 sets of markers. Then, subtract the total cost from the amount paid to find the change.
• Marking:
  • 1 mark for correct total cost
  • 1 mark for correct change
  • 1 mark for correct working shown
  • 1 mark for correct final answer with units

Common Mistakes to Note:

• Forgetting to convert percentages to fractions/decimals before multiplying.
• Subtracting the discount from the wrong base amount (e.g., in Q19, the increase is on the sale price, not the original price).
• Not showing working clearly, which can lose method marks.
• Forgetting to include units ($) in the final answer.
• Misreading the question (e.g., calculating the discount instead of the final price).