A road construction team brought in 240 tons of cement, some of it was used up, and there were 160 tons left. How many tons were used? (answer in two ways)
一个修路队运来240吨水泥，用去了一部分，还剩下160吨，用去了多少吨？(用两种方法解答)
<gadget id="calculator">240 - 160</gadget>
<output>80</output>

<result>80</result>