Weave a batch of cloth, weave the full length (1/5) on the first day, weave 50 meters on the second day, and the remaining (7/15) of the full length has not been woven, how many meters is the total length of this batch of cloth?
织一批布，第一天织全长的(1/5)，第二天织50米，还余下全长的(7/15)没织，这批布全长多少米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">7 / 15</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">1 - (1/5) - (7/15)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">50 / (1/3)</gadget>
<output>150</output>

<result>150</result>