(1/5) of a number is 20 less than its (1/3), find this number.
一个数的(1/5)比它的(1/3)少20，求这个数．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/3) - (1/5)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">20 / (2/15)</gadget>
<output>150</output>

<result>150</result>