Read the story and picture what is happening. Joining or getting more means add. Taking away, giving away or spending means subtract. 'How many more' compares two amounts, so subtract. Equal groups mean multiply, and sharing equally or making groups of the same size mean divide. Do the calculation, then check that the answer makes sense in the story and say it with its unit, such as cents or apples.
Explore this idea with maths tools
Maths you can move
Build 8 + 5
Tap two gold counters to fill the ten-frame.
8 in the frame + 5 waiting. The total stays the same.
Words to know
- altogether
- all the amounts put together
- equal groups
- groups that each have the same number
- difference
- how many more or fewer one amount is than another
Worked examples
Mia has 45 stickers. She gets 30 more. How many stickers does she have altogether?
- 1.Getting more means the amount grows, so add.
- 2.45 + 30 = 75.
- 3.Check: 75 is bigger than 45, which makes sense.
= 75
Sam has 85c and spends 30c. How many cents are left?
- 1.Spending means take away.
- 2.85 - 30 = 55.
- 3.Sam has 55 cents left.
= 55
4 bags have 5 apples in each bag. How many apples are there altogether?
- 1.Equal groups: 4 groups of 5.
- 2.4 × 5 = 20, or count 5, 10, 15, 20.
- 3.There are 20 apples.
= 20
For parents
Method: Act out the story with real objects, then choose the operation.
What to say: What is happening in the story? Should the answer be bigger or smaller? Does your answer make sense?
Common mistakes:
- Chooses the wrong operation, for example adding when the story is about taking away or sharing.
- Picks out the first number in the story as the answer instead of working with the numbers.
- Gives the second number in the story as the answer instead of using it.
- Is one out when counting on or back, for example counting the starting number as the first step.
- Leaves out one group when finding the total of equal groups.