What is negative three minus positive eight?

Answer 1

when subtracting negative numbers its helpful to remember the following phrase:

Keep, Change, Change

this means that the sign of the first number stays the same but the other two change, applying it to your problem means that

3-(-8)=?

keep, change, change

3+(+8)=?

3+8=11

Answer 2

-3 - 8 is the same as -3 + -8 which is -11.

Answer 3

11 positive 11 positive 11