(8/21) of (3/4) is B, how much is B?
(3/4)的(8/21)是乙，乙是多少．
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">8 / 21</gadget>
<output>8/21 = around 0.380952</output>

<gadget id="calculator">(3/4) * (8/21)</gadget>
<output>2/7 = around 0.285714</output>

<result>2/7 = around 0.285714</result>