John volunteers at a shelter twice a month for 3 hours at a time.  How many hours does he volunteer per year?
He volunteers 2*12=
<gadget id="calculator">2*12</gadget>
<output>24</output>
24 times a year.
So he volunteers for 24*3=
<gadget id="calculator">24*3</gadget>
<output>72</output>
72 hours.

<result>72</result>