Lisa, Jack, and Tommy earned $60 from washing cars all week. However, half of the $60 was earned by Lisa. Tommy earned half of what Lisa earned. How much more money did Lisa earn than Tommy?
Lisa earned $60 * 1/2 = $
<gadget id="calculator">60*1/2</gadget>
<output>30</output>
30.
Tommy earned $30 * 1/2 = $
<gadget id="calculator">30*1/2</gadget>
<output>15</output>
15.
Lisa earned $30 - $15 = $
<gadget id="calculator">30-15</gadget>
<output>15</output>
15 more than Tommy.

<result>15</result>