Two ropes with a length of 1 meter are cut off from the first (3/5), and the same length is cut off from the second, how many meters are left, the lengths of the two ropes are equal.
两根长1米的绳子，从第一根上截去(3/5)，从第二根上截去同样长一段后，还剩多少米，两根绳子截去的长度相等．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 * (2/5)</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>