31 plus what equals 20?

This is how to calculate "31 plus what equals 20?" In other words, 31 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:

31 + what = 20

To solve this equation, we first add -31 to each side of the equal sign like this:

31 - 31 + what = 20 - 31

Then, we do the calculation to get the answer to "31 plus what equals 20?" as follows:

What = -11

The answer to "31 plus what equals 20?" is -11. You know this answer is correct because 31 plus -11 equals 20.

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

31 plus what equals 21?
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.