9 plus what equals 40?

This is how to calculate "9 plus what equals 40?" In other words, 9 plus a number equals 40. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

9 + what = 40

To solve this equation, we first add -9 to each side of the equal sign like this:

9 - 9 + what = 40 - 9

Then, we do the calculation to get the answer to "9 plus what equals 40?" as follows:

What = 31

The answer to "9 plus what equals 40?" is 31. You know this answer is correct because 9 plus 31 equals 40.

Plus What Equals Calculator
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9 plus what equals 41?
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