Primary 3 Money Study Guide

Primary 3 money in three short steps: making up a whole dollar amount, adding and subtracting dollars and cents, and working out change after shopping. Each step has a sum to work through and one question to try.

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How do you add and subtract money in Primary 3?

Ten ten-cents make one dollar.

Money is written in decimal notation: dollars on the left of the point, ten-cents and cents on the right. 10 cents make 1 ten-cent, and 10 ten-cents make $1. So money is added and subtracted in columns, like whole numbers, with the decimal points lined up.

In this chapter, your child learns to:

  • find how much more makes a whole dollar amount, such as $10;
  • add and subtract dollars and cents, renaming across the point;
  • find the total cost of some shopping, then the change.
1

Step 1

Making a whole dollar amount

Subtract what you have from the whole dollar amount. Write $1 as $1.00 and $10 as $10.00, so every place has a digit, and line up the decimal points. The cents places are 0, so rename across the zeros: 1 dollar is 10 ten-cents, and 1 ten-cent is 10 cents.

Tap Next place

$10$11010¢031¢05..−
Aisyah has 35 cents. How much more does she need to have $1? Write $1.00 on top and $0.35 below, points lined up. Tap Next place.
Try it

Siti has $3.40. How much more does she need to have $5?

▶ Watch the lesson: Whole dollar amountsPractise 7 questions →
2

Step 2

Adding and subtracting dollars and cents

Line up the decimal points. Dollars sit on the left of the point, ten-cents and cents on the right. Start with the cents. When adding makes 10 ten-cents or more, rename 10 of them as $1, which crosses the point to the dollars. When subtracting, rename the other way: $1 becomes 10 ten-cents.

Tap Next place

$101$12410¢681¢55..+
Kavin buys a storybook for $12.65 and a water bottle for $4.85. Find the total price: $12.65 + $4.85. Tap Next place.
Try it

Find $6.75 + $2.48.

▶ Watch the lesson: Dollars and centsPractise 7 questions →
3

Step 3

Money word problems with change

Find the total cost first. Add the prices of everything bought, counting an item twice if two are bought. Then subtract the total cost from the money paid, never just one price. What is left over is the change, or the money left.

Tap to fill the bar

Kavin buys bread for $2.60 and noodles for $1.30. He pays with a $5 note. How much change does he receive?

$5.00 paid
The long bar is Kavin's $5 note. Tap Show the shopping.
Try it

Wei buys a pen for $1.85 and a ruler for $0.95. He pays with a $5 note. How much change does he receive?

▶ Watch the lesson: Shopping and changePractise 6 questions →Practise 12 mixed questions →

Primary 3 money questions, worked step by stepWork each sum on paper with the points lined up. Then open the hint, or show the working a line at a time.

Whole dollarsBasic

Nurul has 45 cents. How much more money does she need to have $1?

Write $1 as $1.00 and 45 cents as $0.45. Subtract, renaming across the zeros.
  1. Amount needed = $1.00 minus $0.45, with the points lined up.
  2. Rename $1 as 10 ten-cents, then 1 ten-cent as 10 cents: 9 ten-cents and 10 cents.
  3. Cents: 10 minus 5 is 5. Ten-cents: 9 minus 4 is 5. Dollars: 0. So $0.55.
  4. Check: $0.45 + $0.55 = $1.00.
Answer: $0.55 (55 cents)
Dollars and centsIntermediate

A school bag costs $29.75 and a water bottle costs $17.65. What is the total price?

Add with the decimal points lined up. Start with the cents and rename whenever a place makes 10.
  1. Cents: 5 + 5 = 10. Write 0 and carry 1 ten-cent.
  2. Ten-cents: 7 + 6 + 1 = 14. Write 4 and carry $1.
  3. Dollars: 9 + 7 + 1 = 17. Write 7 and carry 1 ten.
  4. Tens: 2 + 1 + 1 = 4.
  5. Total price = $29.75 + $17.65 = $47.40.
Answer: $47.40
Dollars and centsIntermediate

Hui Min had $24.20. She spent $7.85 on a book. How much money did she have left?

Write $24.20 on top and $7.85 below. Each place needs renaming from the place on its left.
  1. Cents: 0 minus 5 needs more. Rename 1 ten-cent as 10 cents: 10 minus 5 is 5.
  2. Ten-cents: 1 minus 8 needs more. Rename $1 as 10 ten-cents: 11 minus 8 is 3.
  3. Dollars: 3 minus 7 needs more. Rename 1 ten as 10 dollars: 13 minus 7 is 6. Tens: 1.
  4. Money left = $16.35. Check: $16.35 + $7.85 = $24.20.
Answer: $16.35
Shopping and changeIntermediate

Priya buys 2 notebooks at $2.35 each and a pencil case for $4.80. She pays with a $10 note. How much change does she receive?

She buys two notebooks, so add $2.35 twice. Find the total cost before the change.
  1. Total cost = $2.35 + $2.35 + $4.80.
  2. Cents: 5 + 5 + 0 = 10, write 0. Ten-cents: 3 + 3 + 8 + 1 = 15, write 5. Dollars: 2 + 2 + 4 + 1 = 9. Total cost = $9.50.
  3. Change = $10.00 minus $9.50. Cents: 0. Rename across the zero for 10 ten-cents: 10 minus 5 is 5. Dollars: 9 minus 9 is 0.
  4. Change = $0.50 (50 cents).
Answer: $0.50
Shopping and changeChallenge

Jun Wei buys a kite and a yo-yo with a $20 note. His change is $6.45. The yo-yo costs $3.90. How much does the kite cost?

The change is what is left after the total cost. Find the total cost from the $20 and the change first.
  1. Total cost = $20.00 minus $6.45 = $13.55.
  2. The total cost is the kite and the yo-yo together, so cost of the kite = $13.55 minus $3.90.
  3. Ten-cents: rename $1, 15 minus 9 is 6. Dollars: rename 1 ten, 12 minus 3 is 9. Kite = $9.65.
  4. Check: $9.65 + $3.90 = $13.55, and $13.55 + $6.45 = $20.00.
Answer: $9.65
4

Step 4

Check yourself

Five money sums: one for each step and one mixed. Tap an answer for the reason, and the link shows which set to try next.

1. How much more than $0.65 makes $1?

2. Find $8.56 + $3.74.

3. Find $13.20 − $4.65.

4. Ali buys a sandwich for $2.40 and a drink for $1.75. He pays with a $10 note. How much change does he receive?

5. Hana buys a cap and a towel with a $20 note. Her change is $3.70. The cap costs $9.55. How much does the towel cost?

0/5
Answer all five to see where to practise next.
For parents

Hand your child some real coins. Swapping ten ten-cent coins for a $1 coin is the renaming in every money sum here. Before each tap of Next place, ask your child to say the renaming first, such as "$1 is 10 ten-cents, so 3 ten-cents become 13."

On a shopping trip, let your child add two prices on paper and work out the change before the cashier does. Ask which number is the total cost before any subtracting starts. Do the worked examples on paper and open one line at a time to compare.

More study guides

Before this: Addition and Subtraction Within 10 000Next: Multiplication Tables of 6, 7, 8 and 9Primary 3 More Word Problems study guidePrimary 4 Decimals study guidePrimary 4 Four Operations of Decimals study guide
Lessons and practice

P3 Money lessons and practice

3 lesson videos and 32 questions across three subtopics, from Basic to Challenge, each with a worked solution.

Watch and practise →