Jill bought 5 packs of red bouncy balls and 4 packs of yellow bouncy balls. Each package contained 18 bouncy balls. How many more red bouncy balls than yellow bouncy balls did Jill buy?
Jill bought 5 packs * 18 red balls = <T>multiply(5, 18)=90 red balls.
Jill bought 4 packs * 18 yellow balls = <T>multiply(4, 18)=72 red balls.
Jill had 90 red – 72 yellow = <T>subtract(90, 72)=18 more red balls.
