9 plus what equals 8?

This is how to calculate "9 plus what equals 8?" In other words, 9 plus a number equals 8. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

9 + what = 8

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

9 - 9 + what = 8 - 9

Then, we do the calculation to get the answer to "9 plus what equals 8?" as follows:

What = -1

The answer to "9 plus what equals 8?" is -1. You know this answer is correct because 9 plus -1 equals 8.

Plus What Equals Calculator
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