John decided to buy 10 pins for himself.  They are normally $20 each but they were on sale for 15% off.  How much did he spend on pins?
The sell reduced the price of each pin by 20*.15=$
<gadget id="calculator">20*.15</gadget>
<output>3</output>
3.
So he paid 20-3=$
<gadget id="calculator">20-3</gadget>
<output>17</output>
17 per pin.
So the total cost was 17*10=$
<gadget id="calculator">17*10</gadget>
<output>170</output>
170.

<result>170</result>