**42 minus what equals 20?**

Here we will show you how to calculate "42 minus what equals 20?" using simple algebra.

For the math problem, "42 minus what equals 20?", we can make it into an algebra equation as follows:

42 - X = 20

Then, we solve for X. To solve for X, we first subtract 42 from both sides:

42 - 42 - X = 20 - 42

-X = -22

Next, you multiply each side by -1 to remove the minus from the X:

-X(-1) = -22(-1)

X = 22

Therefore, the answer to "42 minus what equals 20?" is 22 as illustrated below:

42 - 22 = 20