The ratio of number A to number B is 4:5, then number A is the number of number B.
甲数和乙数的比是4：5，则甲数是乙数的多少．
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>