There is a piece of cloth, (2/5) meter is used for the first time, (1/3) meter is used for the second time, and (1/5) meter is left, how many meters is this cloth originally? (Solution by equation).
有一块布，第一次用去(2/5)米，第二次用去(1/3)米，还剩(1/5)米，这块布原来有多少米？(用方程解)．
<gadget id="calculator">4 / 15</gadget>
<output>4/15 = around 0.266667</output>

<result>4/15 = around 0.266667</result>