The number of A is (4/7), the number of B is (3/8) of the number of A, what is the number of B.
甲数是(4/7)，乙数是甲数的(3/8)，乙数是多少．
<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(4/7) * (3/8)</gadget>
<output>3/14 = around 0.214286</output>

<result>3/14 = around 0.214286</result>