40 plus what equals 9?

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

40 + what = 9

To solve this equation, we first add -40 to each side of the equal sign like this:

40 - 40 + what = 9 - 40

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

What = -31

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

Plus What Equals Calculator
Here you can calculate a similar problem:

40 plus what equals 10?
Do you think you can solve a similar problem on your own? Try to figure out the next problem on our list and then go here to check the answer.