Use reasoning to lead to the answer of the following question:
A band's members each earn $20 per gig. If there are 4 members and they've earned $400, how many gigs have they played?

5
The band earns $80 per gig because 4 x 20 = 80.

They played 5 gigs because 400 / 80 = 5.

.

Therefore, the answer is 5