pile of coal was originally planned to be transported by small trucks, 1.2 tons each time, and was transported 7 times. Later, it was transported by large trucks, and it was transported 2 times.
一堆煤，原计划用小车运，每次运1.2吨，7次运完，后来改用大车运，2次就运完了，大车每次比小车多运多少吨？
<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">1.2 * (7/2)</gadget>
<output>4.2</output>

<gadget id="calculator">4.2 - 1.2</gadget>
<output>3</output>

<result>3</result>