John buys 10 packs of magic cards.  Each pack has 20 cards and 1/4 of those cards are uncommon.  How many uncommon cards did he get?
Each pack has 20/4 = 
<gadget id="calculator">20/4</gadget>
<output>5</output>
5 uncommons.
So he got 10*5 = 
<gadget id="calculator">10*5</gadget>
<output>50</output>
50 uncommons.

<result>50</result>