89 plus what equals 20?

This is how to calculate "89 plus what equals 20?" In other words, 89 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:

89 + what = 20

To solve this equation, we first add -89 to each side of the equal sign like this:

89 - 89 + what = 20 - 89

Then, we do the calculation to get the answer to "89 plus what equals 20?" as follows:

What = -69

The answer to "89 plus what equals 20?" is -69. You know this answer is correct because 89 plus -69 equals 20.

Plus What Equals Calculator
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89 plus what equals 21?
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