The sixth grade is charging $9 per car to wash cars. The fifth grade is charging $8.50 per car. Suppose each grade washes 50 cars. How much more money will the sixth grade earn?

6th graders make $9 per car. $9 times 50 cars

5th graders make $8.50 per car. $8.50 times cars

6th graders earn $450 after washing 50 cars.

5th graders earn $425 after washing 50 cars

$450-$425=$25

The 6th graders make $25 more than the 5th graders.