Addition

What is addition?

Addition means putting groups together to find how many there are altogether. If you have 3 red cars and 2 blue cars, you have 5 cars in all.

We write it as 3 + 2 = 5.

Words that tell you to add include altogether, in all, total, plus, more and both.

Ways to add

1. Count all. Put out 6 counters and 5 counters, then count every one: 11.

2. Count on. Start at the bigger number and count on the smaller one. For 6 + 5, start at 6 and count 7, 8, 9, 10, 11. It’s faster than counting all.

3. Use a number line. Start at 6 and make 5 jumps to the right. You land on 11.

4. Use doubles. Doubles facts are easy to remember: 5 + 5 = 10. So 5 + 6 is one more: 11. This is called "doubles plus one".

5. Make ten. Ten is a friendly number. For 8 + 5, take 2 from the 5 to fill up the 8 to 10, then add the 3 left over: 10 + 3 = 13.

Order doesn’t matter

3 + 5 and 5 + 3 both make 8. You can always swap the numbers in an addition. Put the bigger number first and count on the smaller one: it saves time.

Adding zero

Adding 0 changes nothing: 7 + 0 = 7.

Doubles to learn

Worked examples

Example 1: 6 + 5 = ?

Start at 6 and count on 5: 7, 8, 9, 10, 11. The sum is 11.

Example 2: Lily has 4 shells. She finds 3 more. How many does she have?

"More" means add. 4 + 3 = 7 shells.

Example 3: 9 + 4 = ?

Make ten: 9 + 1 = 10, then 3 more is 13.

Common mistakes

• Counting the starting number again. For 6 + 5, don’t say "6, 7, 8, 9, 10". Start counting at the next number.
• Counting on the bigger number instead of starting with it.
• Forgetting that order doesn’t matter, so you do extra work.

Try it yourself

1. 4 + 4 =
2. 7 + 2 =
3. 2 + 7 =
4. 8 + 6 =
5. Tom has 5 apples and gets 5 more. How many now?

Answers: 1) 8 2) 9 3) 9 4) 14 5) 10

Quick recap

• Addition joins groups to make a sum.
• Count on from the bigger number.
• Doubles and make ten are quick tricks.
• Order doesn’t change the sum.