Jason has a moray eel that eats 20 guppies a day and 5 betta fish who each eat 7 guppies a day. How many guppies per day does she need to buy?
First find the total number of guppies the betta fish need: 5 fish * 7 guppies/fish = 
<gadget id="calculator">5*7</gadget>
<output>35</output>
35 guppies.
Then add the number of guppies the eel needs to find the total number needed: 35 guppies + 20 guppies = 
<gadget id="calculator">35+20</gadget>
<output>55</output>
55 guppies.

<result>55</result>