John's camera broke so he decided to rent one for 4 weeks.  It was a $5000 camera and the rental fee was 10% of the value per week.  His friend who was there when it broke agreed to pay 40% of the rental fee.  How much did John pay?
The rental fee is 5000*.1=$
<gadget id="calculator">5000*.1</gadget>
<output>500</output>
500 per week.
So it cost 500*4=$
<gadget id="calculator">500*4</gadget>
<output>2_000</output>
2000.
His friend pays 2000*.4=$
<gadget id="calculator">2000*.4</gadget>
<output>800</output>
800.
So he pays 2000-800=$
<gadget id="calculator">2000-800</gadget>
<output>1_200</output>
1200.

<result>1_200</result>