piece of cloth is used to make clothes (5/9), and 4 meters is used to make other things. At this time, the remaining cloth is the original (2/5). How many meters is this piece of cloth?
一匹布，做衣服用去(5/9)，做其他用去4米，这时剩下的布是原来的(2/5)，这匹布有多少米？
<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

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

<gadget id="calculator">1 - (5/9) - (2/5)</gadget>
<output>2/45 = around 0.044444</output>

<gadget id="calculator">4 / (2/45)</gadget>
<output>90</output>

<result>90</result>