78 plus what equals 12?

This is how to calculate "78 plus what equals 12?" In other words, 78 plus a number equals 12. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

78 + what = 12

To solve this equation, we first add -78 to each side of the equal sign like this:

78 - 78 + what = 12 - 78

Then, we do the calculation to get the answer to "78 plus what equals 12?" as follows:

What = -66

The answer to "78 plus what equals 12?" is -66. You know this answer is correct because 78 plus -66 equals 12.

Plus What Equals Calculator
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