45 plus what equals 20?

This is how to calculate "45 plus what equals 20?" In other words, 45 plus a number equals 20. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

45 + what = 20

To solve this equation, we first add -45 to each side of the equal sign like this:

45 - 45 + what = 20 - 45

Then, we do the calculation to get the answer to "45 plus what equals 20?" as follows:

What = -25

The answer to "45 plus what equals 20?" is -25. You know this answer is correct because 45 plus -25 equals 20.

Plus What Equals Calculator
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45 plus what equals 21?
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