John takes a 10-minute shower every other day for 4 weeks. If his shower uses 2 gallons of water per minute.  How much water does he use in those 4 weeks?
There are 4*7=
<gadget id="calculator">4*7</gadget>
<output>28</output>
28 days in those 4 weeks.
That means he takes 28/2=
<gadget id="calculator">28/2</gadget>
<output>14</output>
14 showers.
So he takes a total of 14*10=
<gadget id="calculator">14*10</gadget>
<output>140</output>
140 minutes of showers.
So he uses 2*140=
<gadget id="calculator">2*140</gadget>
<output>280</output>
280 gallons of water.

<result>280</result>