Mark constructed a deck that was 30 feet by 40 feet.  It cost $3 per square foot.  He then paid an extra $1 per square foot for sealant.  How much did he pay?
The deck is 30*40=
<gadget id="calculator">30*40</gadget>
<output>1_200</output>
1200 square feet.
He pays 3+1=$
<gadget id="calculator">3+1</gadget>
<output>4</output>
4 per square foot.
So he paid 1200*4=$
<gadget id="calculator">1200*4</gadget>
<output>4_800</output>
4800.

<result>4_800</result>