The construction team transported a pile of 120 tons of construction materials, and transported away 3/8 of the total on the first day, and 30% of the total on the second day. Two days later, how many tons less building materials were there than in the original?
工程队运一堆120吨的建筑材料，第一天运走了总数的(3/8)，第二天又运走了总数的30%．两天后这堆建筑材料比原来少了多少吨？
<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">120 * (3/8)</gadget>
<output>45</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">120 * (3/10)</gadget>
<output>36</output>

<gadget id="calculator">45 + 36</gadget>
<output>81</output>

<result>81</result>