There are 516 cars in a parking lot. One-third are blue, one-half are red, and the rest are black. How many black cars are on the lot?
Blue = 516 * (1/3) = 
<gadget id="calculator">516*(1/3)</gadget>
<output>172</output>
172 cars.
Red = 516 * (1/2) = 
<gadget id="calculator">516*(1/2)</gadget>
<output>258</output>
258.
Black = 516 - (172 + 258) = 86.
There are 86 black cars on the lot.

<result>86</result>