Question

What is the value of the written problem (-9)-(-1)

Answer 1

the answer is -8 because you start at -9, go back -1, which equals -8 

Answer 2

(-9)-(-1) can be solved by using the method (stay, add, flip)
you keep the (-9) the same, change the (-) sign to (+), and flip the (-1) to (1). Your final equation becomes -9+1, simple math. Your answer is -8. I hope I helped you out.