(3/4) of a number is (12/21), what is this number?
一个数的(3/4)是(12/21)，这个数是多少？
<gadget id="calculator">12 / 21</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">(4/7) / (3/4)</gadget>
<output>16/21 = around 0.761905</output>

<result>16/21 = around 0.761905</result>