80 plus what equals 78?

This is how to calculate "80 plus what equals 78?" In other words, 80 plus a number equals 78. What is that number? We start by converting this word problem into an equation where "what" is what we want to solve:

80 + what = 78

To solve this equation, we first add -80 to each side of the equal sign like this:

80 - 80 + what = 78 - 80

Then, we do the calculation to get the answer to "80 plus what equals 78?" as follows:

What = -2

The answer to "80 plus what equals 78?" is -2. You know this answer is correct because 80 plus -2 equals 78.

Plus What Equals Calculator
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