CPM Homework Help : CC2 Problem 4-6

Simplify the expressions below.

Solution (a):

Draw 8 pluses. Then draw 13 minuses. Remove 4 minuses. Then 8 of the Plus - Minus combinations are 0. Thus only 1 minus remains.

Answer (a):

$-1$

$-7+3-20$
Hint (c):
If you start at $0$ , move to left $7$ , right $3$ , and left $20$ , where do you end up?