8 plus what equals 15?

This is how to calculate "8 plus what equals 15?" In other words, 8 plus a number equals 15. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

8 + what = 15

To solve this equation, we first add -8 to each side of the equal sign like this:

8 - 8 + what = 15 - 8

Then, we do the calculation to get the answer to "8 plus what equals 15?" as follows:

What = 7

The answer to "8 plus what equals 15?" is 7. You know this answer is correct because 8 plus 7 equals 15.

Plus What Equals Calculator
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