Hawkeye is driving to his aunt. He has to charge his battery for $3.5 per charge. If he charged his battery four times, and his battery charging budget was $20, how much money was he left with when he reached his aunt's place?
If each battery charge costs $3.5, the total expense of 4 battery charges is 4*3.5 = $
<gadget id="calculator">4*3.5</gadget>
<output>14</output>
14.
After his expense on battery charging, his balance was 20-14 = $
<gadget id="calculator">20-14</gadget>
<output>6</output>
6.

<result>6</result>