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= 
<gadget id="calculator">100/4</gadget>
<output>25</output>
25 dollars on a new video game.
So, after the video game purchase, Mary was left with 100 - 25 = 
<gadget id="calculator">100-25</gadget>
<output>75</output>
75 dollars.
Mary then bought swimming goggles for 75/5 = 
<gadget id="calculator">75/5</gadget>
<output>15</output>
15 dollars.
Mary had 75 - 15 = 
<gadget id="calculator">75-15</gadget>
<output>60</output>
60 dollars left.

<result>60</result>