(2/3) of a number is 4 more than (3/5) of this number, what is this number?
一个数的(2/3)比这个数的(3/5)多4，这个数是多少．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(2/3) - (3/5)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">4 / (1/15)</gadget>
<output>60</output>

<result>60</result>