Gerald had 20 toy cars. He donated 1/4 of his toy cars to an orphanage. How many toy cars does Gerald have left?
Gerald gave away 20 x 1/4 = 
<gadget id="calculator">20*1/4</gadget>
<output>5</output>
5 of his toy cars.
Therefore, he is left with 20 - 5 = 
<gadget id="calculator">20-5</gadget>
<output>15</output>
15 toy cars.

<result>15</result>