Elsa gets 500 MB of cell phone data each month. If she spends 300 MB watching Youtube and 2/5 of what's left on Facebook, how many MB of data does she have left?
First subtract the 300 MB Elsa spent on YouTube: 500 MB - 300 MB = 
<gadget id="calculator">500-300</gadget>
<output>200</output>
200 MB.
Then multiply 200 MB by 2/5th to find out how much data Elsa spent on Facebook: 200 MB * 2/5 = 
<gadget id="calculator">200*2/5</gadget>
<output>80</output>
80 MB.
Finally, subtract the data Elsa spent on Facebook from the 200 MB: 200 MB - 80 MB = 
<gadget id="calculator">200-80</gadget>
<output>120</output>
120 MB.

<result>120</result>