At a pool party, there are 4 pizzas cut into 12 slices each.  If the guests eat 39 slices, how many slices are left?
There's a total of 4 x 12 = 
<gadget id="calculator">4*12</gadget>
<output>48</output>
48 slices.
After the guests eat, there are 48 - 39 = 
<gadget id="calculator">48-39</gadget>
<output>9</output>
9 pieces.

<result>9</result>