Dirk sells amulets at a Ren Faire.  He sells for 2 days and each day he sells 25 amulets.  Each amulet sells for 40 dollars and they cost him 30 dollars to make.  If he has to give 10% of his revenue to the faire, how much profit did he make?
He sold 2*25=
<gadget id="calculator">2*25</gadget>
<output>50</output>
50 amulets.
So he made 40*50=$
<gadget id="calculator">40*50</gadget>
<output>2_000</output>
2000.
The faire took 2000*.1=$
<gadget id="calculator">2000*.1</gadget>
<output>200</output>
200.
So he kept 2000-200=$
<gadget id="calculator">2000-200</gadget>
<output>1_800</output>
1800.
The amulets cost 50*30=$
<gadget id="calculator">50*30</gadget>
<output>1_500</output>
1500 to make.
So he had a profit of 1800-1500=$
<gadget id="calculator">1800-1500</gadget>
<output>300</output>
300.

<result>300</result>