Jenny and Mark are throwing bottle caps. Jenny's bottlecap flies 18 feet straight, then bounces off a street light and flies another 1/3 of the distance it already went. Mark's bottle cap flies 15 feet forward, then bounces off a window and flies twice as far as it already did. How much further did Mark's bottle cap go than Jenny's?
First find 1/3 of the distance Jenny's bottlecap went straight: 18 feet / 3 = 
<gadget id="calculator">18/3</gadget>
<output>6</output>
6 feet.
Then add that to the distance it flew straight to find the total distance it traveled: 6 feet + 18 feet = 
<gadget id="calculator">6+18</gadget>
<output>24</output>
24 feet.
Then find twice the distance Mark's bottlecap went straight: 15 feet * 2 = 
<gadget id="calculator">15*2</gadget>
<output>30</output>
30 feet.
Then add that distance to the distance it flew straight to find the total distance it traveled: 30 feet + 15 feet = 
<gadget id="calculator">30+15</gadget>
<output>45</output>
45 feet.
Then subtract the distance Jenny's bottlecap traveled from the distance Mark's traveled to find the difference: 45 feet - 24 feet = 
<gadget id="calculator">45-24</gadget>
<output>21</output>
21 feet.

<result>21</result>