# Question Video: Using a Known Subtraction Equation to Check an Addition Equation Mathematics • 2nd Grade

You know that 37 − 24 = 13. Is it true that 13 + 24 = 37?

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### Video Transcript

You know that 37 subtract 24 equals 13. Is it true that 13 plus 24 equals 37?

In this question, we’re told that 37 take away 24 equals 13. 37 is the whole amount that we start with. We subtract 24, and we’re left with 13. 37 is the whole amount, and the two parts are 24 and 13. We’re asked if it’s true that 13 plus 24 equals 37. What do you notice about these three numbers? We have the same three numbers in our addition calculation, as we do in our subtraction calculation. 37 is the whole amount that we started with. We subtracted 24, and we were left with 13. So, 13 plus 24 equals 37.

We can quickly check this calculation to make sure that it’s true. Let’s start by adding the ones. Three ones and four ones makes seven ones. We know that’s correct. Let’s just add in the tens column. One 10 plus two 10s equals three 10s. It is true that 13 plus 24 equals 37.