At the circus, the clown has 3 dozen balloons on a string in his hand.  3 boys and 12 girls buy a balloon each.  How many balloons is the clown still holding?
The clown is holding 3 x 12 = 
<gadget id="calculator">3*12</gadget>
<output>36</output>
36 balloons.
This many children buy a balloon: 3 + 12 = 
<gadget id="calculator">3+12</gadget>
<output>15</output>
15 kids.
After the children buy the balloons, the clown is holding this many in his hand 36 - 15 = 
<gadget id="calculator">36-15</gadget>
<output>21</output>
21 balloons.

<result>21</result>