A batch of goods was shipped, originally planned to be shipped 7 times, but it turned out that it only took 5 times to be shipped. What percentage of this batch of goods is actually shipped more than the original plan each time?
装运一批货物，原计划7次运完，结果只要5次就运完了．实际比原计划每次多运这批货物的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/5) - (1/7)</gadget>
<output>2/35 = around 0.057143</output>

<result>2/35 = around 0.057143</result>