A chef needs to make french fries.  He can get 25 fries out of 1 potato.  He has 15 potatoes and he needs 200 fries.  How many potatoes will he have leftover?
To make 200 fries he will need 200 / 25 fries per potato = 
<gadget id="calculator">200/25</gadget>
<output>8</output>
8 potatoes.
He has 15 potatoes - 8 potatoes = 
<gadget id="calculator">15-8</gadget>
<output>7</output>
7 leftover potatoes.

<result>7</result>