John builds a model rocket that can travel 500 ft in the air.  He builds a second rocket that can travel twice as high.  What is the combined height of the two rockets?
The second rocket goes 500*2=
<gadget id="calculator">500*2</gadget>
<output>1_000</output>
1000 feet.
So the total height is 500+1000=
<gadget id="calculator">500+1000</gadget>
<output>1_500</output>
1500 feet.

<result>1_500</result>