The answer of 9-6=A(or any other letter) A=3.so for an addition problem just do A+6=9 or 6+A=9 .You do this because you are just doing the inverse operation.
For this case, the first thing we must do is define a variable: x: unknown number We then have the following equation: We are going to rewrite the equation as an addition equation. To do this, we add 6 on both sides of the equation: Let's rewrite the left side of the equation: Answer: an addition equation that can help you find 9-6 is: