Video: Relationship Between Addition and Subtraction within 100

In this video, we will learn how to use addition to check subtraction and identify the related addition equation that can be solved to check the answer.

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Video Transcript

Relationship between Addition and Subtraction within 100.

In this video, we’re going to learn about the relationship between addition and subtraction. Here we have 10 beads. One is green and nine are orange. We can use the three numbers one, nine, and 10 to make two addition facts and two subtraction facts. One plus nine equals 10 and nine plus one equals 10. These are addition facts. We can also make two subtraction facts. 10 take away one is nine and 10 take away nine is one. We call addition and subtraction inverse operations.

Inverse operations are operations which are opposite and undo each other. So we can add one and nine to make 10 and then take it apart by taking away one to make nine. We can use the inverse operation to help us check our calculations. In this example, we’re going to solve the problem using subtraction and then we’re going to use the inverse addition to help us check our answer.

The question tells us that Sophia and Benjamin have been asked to solve 96 take away 45. Sofia solves it and gets an answer of 51. Benjamin solves it and gets an answer of 31. Who’s correct? Use the vertical column method to find out.

So the question tells us to solve 96 take away 45. Using our vertical column method, first we subtract five from six, which leaves us with one, then we work out nine take away four, which is five. 51 is the answer that Sophia gave. So Sophia is correct. Now we have to check our answer using the inverse operation. What number do you add to 45 to get 96? Now instead of subtracting, we need to add because addition and subtraction are inverse operations. We need to check if 45 add 51 equal 96. Five plus one is six and four plus five is nine. 96 take away 45 is 51. 45 plus 51 is 96. The number we had to add to 45 to get 96 is 51.

In this video, we’ve learned that addition and subtraction are inverse operations and we can use the inverse to help us check our calculations.

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