Addition Within 10
Kindergarten · Math · Study Guide
Addition means putting groups together to find out how many you have in all. Let's add up to 10!
Addition is what you do when you combine two groups into one bigger group. If you have 2 apples and your friend gives you 3 more, you put them together and count them all — that gives you 5 apples! We write this as: 2 + 3 = 5.
The plus sign (+) tells us to add, and the equals sign (=) tells us the answer is coming. The answer to an addition problem is called the sum. So in 2 + 3 = 5, the sum is 5.
You can add using your fingers! Hold up 3 fingers on one hand and 4 fingers on the other. Count all your fingers together — 1, 2, 3, 4, 5, 6, 7. The sum is 7! Your fingers are a built-in adding machine.
Another strategy is to count on. Start with the bigger number in your head and count up. For 6 + 2, start at 6 and count up 2 more: '7, 8!' The sum is 8. This is faster than counting all the way from 1 every time.
Here's a cool math secret: you can add numbers in any order and get the same answer! 3 + 4 = 7 and 4 + 3 = 7 too. This is called the commutative property — but you just need to know that switching the order of numbers in addition doesn't change the answer.
| Problem | Sum | Story |
|---|---|---|
| 1 + 1 = 2 | 2 | 1 cat + 1 cat = 2 cats |
| 2 + 3 = 5 | 5 | 2 apples + 3 apples = 5 apples |
| 4 + 4 = 8 | 8 | 4 red blocks + 4 blue blocks = 8 blocks |
| 5 + 5 = 10 | 10 | 5 fingers + 5 fingers = 10 fingers |
| 6 + 2 = 8 | 8 | 6 crayons + 2 crayons = 8 crayons |
| 7 + 3 = 10 | 10 | 7 stars + 3 stars = 10 stars |
| 0 + 9 = 9 | 9 | 0 more + 9 grapes = 9 grapes |
Key terms
- addition
- Combining two or more groups to find out how many there are in all
- plus sign (+)
- The symbol that means 'add' or 'put together'
- sum
- The answer when you add two numbers together
- equals sign (=)
- The symbol that means the answer is on the other side
- count on
- A strategy where you start at the bigger number and count up to add
Practice questions
What is 4 + 3?
- 6
- 8
- 7
- 5
Show answer
Answer: 7
5 + 0 = 5 is a true addition fact.
Show answer
Answer: True
2 + 6 = ___.
Show answer
Answer: 8
Mia has 3 stickers. She gets 4 more. How many does she have in all?
- 6
- 8
- 5
- 7
Show answer
Answer: 7
3 + 5 gives the same sum as 5 + 3.
Show answer
Answer: True
Fun facts
- Adding any number to zero always gives you that number back! 5 + 0 = 5, 9 + 0 = 9. Zero is called the 'identity element' for addition because it doesn't change your number.
- The + sign was first used in a math book in 1489 by a German mathematician named Johannes Widmann. Before that, people wrote out the word 'plus' or 'and' every time!
- The fastest human calculators in the world can add large numbers in their heads in seconds. With enough practice, your brain can become a lightning-fast adding machine too!
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