(1/4) of a number is 10 less than its (2/5), what is this number?
一个数的(1/4)比它的(2/5)少10，这个数是多少？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(2/5) - (1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">10 / (3/20)</gadget>
<output>200/3 = around 66.666667</output>

<result>200/3 = around 66.666667</result>