If the ratio of the two numbers of A and B is 4:5, how much is A less than B?
甲乙两数之比是4：5，则甲比乙少多少
<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>