The ratio of the three numbers A, B, and C is 5:3:4, and the number B accounts for the sum of the three numbers ((())/(())).
甲、乙、丙三个数的比是5：3：4，乙数占三数之和的((())/(()))．
<gadget id="calculator">5 + 3 + 4</gadget>
<output>12</output>

<gadget id="calculator">3 / 12</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>