42 plus what equals 15?

This is how to calculate "42 plus what equals 15?" In other words, 42 plus a number equals 15. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

42 + what = 15

To solve this equation, we first add -42 to each side of the equal sign like this:

42 - 42 + what = 15 - 42

Then, we do the calculation to get the answer to "42 plus what equals 15?" as follows:

What = -27

The answer to "42 plus what equals 15?" is -27. You know this answer is correct because 42 plus -27 equals 15.

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

42 plus what equals 16?
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.