(5/21) of a number is 4, what is (5/7) of this number
一个数的(5/21)是4，这个数的(5/7)是多少
<gadget id="calculator">5 / 21</gadget>
<output>5/21 = around 0.238095</output>

<gadget id="calculator">4 / (5/21)</gadget>
<output>84/5 = around 16.8</output>

<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">(84/5) * (5/7)</gadget>
<output>12</output>

<result>12</result>