15% of a number is 20 less than its (1/5), what is the number?
一个数的15%比它的(1/5)少20，这个数是多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">(1/5) - (3/20)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">20 / (1/20)</gadget>
<output>400</output>

<result>400</result>