John buys 2 dozen cookies.  He eats 3.  How many cookies does he have left?
He got 2*12=
<gadget id="calculator">2*12</gadget>
<output>24</output>
24 cookies.
So he has 24-3=
<gadget id="calculator">24-3</gadget>
<output>21</output>
21 cookies left.

<result>21</result>