John decides to learn how to play the piano.  He buys a piano for $500.  He then hires a teacher for 20 lessons at $40 per lesson but ends up getting a 25% discount.  How much did everything cost?
The normal price of the lessons would be 20*40=$
<gadget id="calculator">20*40</gadget>
<output>800</output>
800.
The discount saves him 800*.25=$
<gadget id="calculator">800*.25</gadget>
<output>200</output>
200.
So the lessons cost him 800-200=$
<gadget id="calculator">800-200</gadget>
<output>600</output>
600.
That means everything costs 500+600=$
<gadget id="calculator">500+600</gadget>
<output>1_100</output>
1100.

<result>1_100</result>