Thirty-six marbles are divided between Mario and Manny in the ratio 4:5. If Manny decided to give 2 marbles to his brother, how many marbles does Manny have now?
The marbles are divided into 4 + 5 = <T>add(4, 5)=9 parts.
Each part consists 36/9 = <T>divide(36, 9)=4.0 marbles.
So Manny had 5 parts x 4 = <T>multiply(5, 4)=20 marbles.
After giving 2 marbles to his brother, he now has 20 - 2 = <T>subtract(20, 2)=18 marbles left.
