John injures his shoulder while lifting weights.  After the injury, his bench press goes down 80%.  After a bit of training, he manages to triple the weight he can bench.  If he started with a 500-pound bench press, what is it now?
He lost 500*.8=
<gadget id="calculator">500*.8</gadget>
<output>400</output>
400 pounds from his bench.
So his bench went to 500-400=
<gadget id="calculator">500-400</gadget>
<output>100</output>
100 pounds.
After training it increased to 100*3=
<gadget id="calculator">100*3</gadget>
<output>300</output>
300 pounds.

<result>300</result>