John visits his parents twice a month.  It takes him 2 hours to drive there at a speed of 70 mph.  Considering the round trip, how many miles a month does he drive when visiting his parents?
His parents live 70*2=
<gadget id="calculator">70*2</gadget>
<output>140</output>
140 miles away.
So he drives 140*2=
<gadget id="calculator">140*2</gadget>
<output>280</output>
280 miles a round trip
280*2 = 
<gadget id="calculator">280*2</gadget>
<output>560</output>
560 miles a month.

<result>560</result>