Negative 9 minus negative 10

You have - 9 - (-10). So when you have a subtraction symbol next to a negative, just like this problem. You will then have a positive 10.

So ...

Negative and a Positive make a [Negative]

Positive and a Negative make a [Negative]

Positive and a Positive make a [Positive]

Negative Negative make a [Positive]

Then you add - 9 and 10. You go closer to the 0. Then you have 1.

1 is your answer - + - is a positive