James pays $1000 for advertising.  It brought 100 customers to his site and 80% of those bought something at the store that cost $25.  How much profit does he gain from the ad?
100*.8=
<gadget id="calculator">100*.8</gadget>
<output>80</output>
80 customers bought something.
That means they were worth 80*25=$
<gadget id="calculator">80*25</gadget>
<output>2_000</output>
2000.
So he gained 2000-1000=$
<gadget id="calculator">2000-1000</gadget>
<output>1_000</output>
1000 from the ad.

<result>1_000</result>