Mark hires a singer for 3 hours at $15 an hour.  He then tips the singer 20%.  How much did he pay?
The cost was 15*3=$
<gadget id="calculator">15*3</gadget>
<output>45</output>
45.
So the tip was 45*.2=$
<gadget id="calculator">45*.2</gadget>
<output>9</output>
9.
So in total, he paid 45+9=$
<gadget id="calculator">45+9</gadget>
<output>54</output>
54.

<result>54</result>