Luigi bought four pizzas for $80.  Each pizza was cut into 5 pieces.  How much did each piece of pizza cost, in dollars?
4 pizzas at $80 per pizza is $80/4 = $
<gadget id="calculator">80/4</gadget>
<output>20</output>
20 per pizza.
If there were 5 pieces per pizza, then each piece was worth $20/5 = $
<gadget id="calculator">20/5</gadget>
<output>4</output>
4.

<result>4</result>