Video: Using the Relationship between Addition and Subtraction to Fluently Subtract 2-Digit Numbers

Sophia and Benjamin have been asked to solve 96 − 45. Sophia solves it and gets an answer of 51. Benjamin solves it and gets an answer of 31. Who is correct? Use the vertical column method to find out. Check your answer using the inverse operation. What number do you add to 45 to get 96?

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Video Transcript

Sophia and Benjamin have been asked to solve 96 subtract 45. Sophia solves it and gets an answer of 51. Benjamin solves it and gets an answer of 31. Who is correct? Use the vertical column method to find out. Check your answer using the inverse operation. What number do you add to 45 to get 96?

First, we need to find the answer to 96 take away 45. Six take away five is one, and nine take away four is five. So the answer is 51. So who was correct, Sophia or Benjamin? Sophia said 51, so she’s correct.

Now we need to check Sophia’s answer using the inverse operation. In other words, what do we add to 45 to get 96? The question is asking us to check if 45 and 51 make 96. Five plus one makes six; four plus five makes nine. So we add 51 to 45 to make 96.

Sophia was correct to say that 96 take away 45 is 51. And we checked her answer using the inverse operation and found that you need to add 51 to 45 to make 96.

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