When we put groups together, we add. Adding makes the group bigger. Today we add numbers up to 20.
Joining
There are 5 birds in a tree. 3 more birds fly in. How many birds are there now?
🐦🐦🐦🐦🐦 + 🐦🐦🐦
We can count on from 5: six, seven, eight. There are 8 birds.
5 + 3 = 8
We say: “five plus three equals eight”.
Two groups make a whole
Kai has 6 red marbles and 4 blue marbles. How many marbles does he have altogether? 6 + 4 = 10.
Hop on the number line
To add 9 + 4, start at 9 and hop 4 steps to the right: 10, 11, 12, 13. So 9 + 4 = 13.
Adding three numbers
3 + 2 + 5: first 3 + 2 = 5, then 5 + 5 = 10.
Adding going down
We can also write sums going down. Line up the numbers on the right.
12 + 5 ──── 17
Adding money
A mango costs 10¢ and a plum costs 5¢. Together they cost 10¢ + 5¢ = 15¢.
TRY ITNumber stories: adding
Read the story. Use the counters or the number line. Tap the answer.
Let’s practise
Try each one. Then tap Show answer to check.
1. 4 + 3 = ☐
Show answer
7
2. 8 + 6 = ☐
Show answer
14
3. 10 + 7 = ☐
Show answer
17
4. 2 + 5 + 3 = ☐
Show answer
10
5. Mia has 9 shells. She finds 5 more. How many shells now?
Show answer
14 shells. 9 + 5 = 14.
6. A pencil costs $5 and a book costs $10. How much altogether?
Show answer
$15.
7. 11 + 8 = ☐ (write it going down)
Show answer
19.
Quick check
1. What happens to a group when we add to it?
Show answer
It gets bigger.
2. Make up a story for 7 + 2 = 9.
Show answer
Any story, for example: 7 ducks were in the pond and 2 more came. Now there are 9 ducks.
3. 6 + 6 + 6 = ☐
Show answer
18.
Maths words
Say these words with a grown-up. Can you use each one in a sentence?
add · plus (+) · equals (=) · altogether · in all · more · total · count on · number sentence
Try it at home
- Use bottle caps or beans to act out adding stories.
- At the shop, add the prices of two small things.
- Tell a grown-up an adding story. They write the number sentence. Then swap.
For parents and teachers
After this lesson, your child should be able to:
- add by joining groups and by putting two parts together to make a whole
- add two or three numbers with totals up to 20
- count on and use a number line to add
- solve adding problems told aloud, in pictures, with money, and written across or going down
- write and make up addition number sentences and stories
Encourage counting on from the bigger number (for 3 + 9, start at 9) rather than counting everything from 1.
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Next: Taking Away within 20
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