Question

What is the mathematical definition of the Subtraction Property of Equality?

Answer 1

when both sides of an equation have the same number subtracted from each of them, so the remaining part of the equation is still equal

Answer 2

I just learned this today. 

In my case, You can add or subtract the same quantity from both sides and retain the equality.

For example: If $a=b$, then $a-c=b-c$

Additive and Subtractive Property of Equality are the Same Thing

Credit to my math Teacher for this