Answer :
18 + (-8) + 11
Adding a negative number is the same as subtracting a positive number. So "18-8" is the same thing as "18+ -8".
18 - 8 + 11
10 + 11
21
Adding a negative number is the same as subtracting a positive number. So "18-8" is the same thing as "18+ -8".
18 - 8 + 11
10 + 11
21
