John buys 5 toys that each cost $3.  He gets a 20% discount.  How much did he pay for everything?
The toys cost 5*3=$
<gadget id="calculator">5*3</gadget>
<output>15</output>
15.
His discount is worth 15*.2=$
<gadget id="calculator">15*.2</gadget>
<output>3</output>
3.
So he pays 15-3=$
<gadget id="calculator">15-3</gadget>
<output>12</output>
12.

<result>12</result>