To build a 600m long canal, 20% of the total length was repaired for the first time, and 35% of the total length was repaired for the second time. How many meters less was the first repair than the second?
修一条长600m的水渠，第一次修了全长的20%，第二次修了全长的35%，第一次比第二次少修多少米？
<gadget id="calculator">35 / 100</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">600 * (7/20)</gadget>
<output>210</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">600 * (1/5)</gadget>
<output>120</output>

<gadget id="calculator">210 - 120</gadget>
<output>90</output>

<result>90</result>