Addition (up to 20)
Adding by Counting On
Addition means putting two groups together to find how many there are in all. We use the sign + (plus) and = (equals) to show the total.
An easy way to add is to count on. To add 5 + 3, start at 5 and count on three more: 6, 7, 8. So 5 + 3 = 8.
Example 1: Add: 6 + 2
Start at 6 and count on 2 more: 7, 8. So 6 + 2 = 8.
Example 2: Add: 7 + 4
Start at 7: 8, 9, 10, 11. So 7 + 4 = 11.
Quick recap
- Addition (+) joins groups to find the total.
- Count on from a number to add quickly.
- The answer comes after the = sign.
✓ Quick check
What is 3 + 5?
3 + 5 = 8.
Count on from 9: 9 + 2 = ?
9 → 10, 11. So 9 + 2 = 11.
Order of Addition and Adding Zero
When we add, the order does not matter. 4 + 6 gives the same answer as 6 + 4 — both equal 10.
Adding zero changes nothing: 8 + 0 = 8, because zero means 'none added'.
Example 1: Is 2 + 7 the same as 7 + 2?
Yes. 2 + 7 = 9 and 7 + 2 = 9.
Example 2: Add: 5 + 0
Adding zero keeps the number the same, so 5 + 0 = 5.
Quick recap
- Order does not change the sum: 6 + 3 = 3 + 6.
- Adding 0 leaves the number unchanged.
✓ Quick check
Which is equal to 6 + 3?
Order does not matter, so 6 + 3 = 3 + 6 = 9.
9 + 0 = ?
Adding zero keeps the number the same: 9 + 0 = 9.
Addition Word Problems
In real life we add to find a total. Words like in all, altogether and total tell us to add the amounts.
Example 1: Riya has 4 red balloons and 5 blue balloons. How many in all?
4 + 5 = 9 balloons.
Example 2: A plate has 7 idlis. Amma adds 3 more. How many now?
7 + 3 = 10 idlis.
Quick recap
- 'In all', 'altogether' and 'total' mean add.
- Add the two amounts to get the total.
✓ Quick check
Aarav has 5 marbles. A friend gives him 4 more. How many marbles now?
5 + 4 = 9 marbles.
There are 6 boys and 6 girls. How many children in all?
6 + 6 = 12 children.
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