Question

Negative 9 minus negative 10

Answer 1

1 is your answer -+- is a positive

Answer 2

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.