A wire is (7/10) meters long. Cut off the full length (1/4) for the first time, and cut off the full length (2/5) for the second time. What fraction of the full length is left?
一根铁丝长(7/10)米．第一次剪去全长的(1/4)，第二次剪去全长的(2/5)．还剩全长的几分之几？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<result>7/20 = around 0.35</result>