What is negative 1 minus 1?

Dealing with negative numbers might be confusing at first, but try and visualise (or draw) a number scale, starting with 0 at the middle and going up the positive numbers above and down the negative numbers below, like this:

(etc.)

^

4 -|

3 -|

2 -|

1 -|

0 -|

-1 -|

-2 -|

-3 -|

-4- |

V

(etc.)

By adding, we effectively move up this number line; by subtracting, we move down it. With negative one minus one, we are starting with minus one, then subtracting positive one, i.e. -1 - (1). So we start at -1, then by subtracting 1 we move down 1 space to -2.

Therefore -1 - 1 = -2