60% of a number is 2.4 more than 40% of it. What is the number?
一个数的60%比它的40%多2.4，这个数是多少．
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(3/5) - (2/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2.4 / (1/5)</gadget>
<output>12</output>

<result>12</result>