Number pairs to ten, or number bonds to ten, are the numbers from and including 1 up to and including 9 put together in pairs that add up to 10. Like this:

Rule

1 and 9, 2 and 8, 3 and 7, 4 and 6, 5 and 5

Knowing number pairs well will help you with future calculations.

Make sure to memorize the number pairs to ten.

Think About This

**How can you use your fingers to find the number pairs to ten? **

You have ten fingers. If you close both your thumbs (2 fingers), you have 8 fingers left stretched out. This is 2 closed and 8 stretched out, which is 10 combined, so now you know that 2 and 8 are number pairs. If you close one hand, then 5 fingers are closed and 5 fingers are stretched out. Adding this together makes 10, so now you know that 5 and 5 are number pairs. In addition to having number pairs to ten, you also have number pairs to five. Use one hand only and see if you can fins the number pairs to five.

$$\text{1and4}\phantom{\rule{2em}{0ex}}\text{2and3}$$ |

And it’s not just five and ten. You can have number pairs to many other numbers.

You can divide the numbers from 0 to 100 into groups of ten, which means whole tens up to 100.

Rule

10, 20, 30, 40, 50, 60, 70, 80, 90

Of these groups of ten you can make number pairs to a hundred. You do this by putting them into pairs.

Rule

10 and 90, 20 and 80, 30 and 70, 40 and 60, 50 and 50

Remember, there are many number pairs to a hundred: All numbers that add up to 100 are number pairs. Some examples of number pairs are therefore 9 and 91, 43 and 57, and 23 and 77.

Think About This

**What will it look like with number pairs to a thousand? Is there a system among the number pairs? **

You added a 0 to move from the digits to the groups of tens, you can go from groups of tens to groups of hundreds by adding another 0. Hundreds look like this:

100, 200, 300, 400, 500, 600, 700, 800, 900

If you put together groups of hundreds which add up to 1000, you get number pairs to 1000. They look like this:

100 and 900 200 and 800 300 and 700 400 and 600 500 and 500

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