On Mary's birthday, her brother surprised her with $100. She spent a quarter of it on a new video game and then used a fifth of what was left on swimming goggles. How much money did she have left?
Mary spent 100/4= <T>divide(100, 4)=25.0 dollars on a new video game.
So, after the video game purchase, Mary was left with 100 - 25 = <T>subtract(100, 25)=75 dollars.
Mary then bought swimming goggles for 75/5 = <T>divide(75, 5)=15.0 dollars
Mary had 75 - 15 = <T>subtract(75, 15)=60 dollars left
