72 plus what equals 81?

This is how to calculate "72 plus what equals 81?" In other words, 72 plus a number equals 81. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

72 + what = 81

To solve this equation, we first add -72 to each side of the equal sign like this:

72 - 72 + what = 81 - 72

Then, we do the calculation to get the answer to "72 plus what equals 81?" as follows:

What = 9

The answer to "72 plus what equals 81?" is 9. You know this answer is correct because 72 plus 9 equals 81.

Plus What Equals Calculator
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72 plus what equals 82?
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