School uniforms. It is planned to use 3.8 meters of cloth for each set, but actually each set saves 0.4 meters. Originally planned to make 680 sets of fabrics for school uniforms, how many more sets were actually produced than planned.
学校制校服．计划每套用布3.8米，实际每套节省了0.4米．原来计划做680套校服的布料，实际比计划多做多少套．
<gadget id="calculator">3.8 - 0.4</gadget>
<output>3.4</output>

<gadget id="calculator">680 / 3.4</gadget>
<output>200</output>

<gadget id="calculator">3.8 * 200</gadget>
<output>760</output>

<gadget id="calculator">760 - 680</gadget>
<output>80</output>

<result>80</result>