The difference between (4/5) minus (2/3) is multiplied by a number to get (2/7), find this number.
(4/5)减(2/3)的差乘一个数得(2/7)，求这个数．
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(4/5) - (2/3)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">(2/7) / (2/15)</gadget>
<output>15/7 = around 2.142857</output>

<result>15/7 = around 2.142857</result>