Gary bought a boat for $9000.  Over the first year it depreciated 30%.  The second year it depreciated another 30%.  The third year it depreciated 20%.  How much is the boat worth after the three years?
After first year:9000(.30)=2700
9000-2700=
<gadget id="calculator">9000-2700</gadget>
<output>6_300</output>
6300.
After second year:6300(.30)=1890
6300-1890=
<gadget id="calculator">6300-1890</gadget>
<output>4_410</output>
4410.
After third year:4410(.20)=882
4410-882=
<gadget id="calculator">4410-882</gadget>
<output>3_528</output>
3528$

<result>3_528</result>