If the ratio of A and B is 5:4, how much less is B than A?
甲、乙两数的比是5：4，则乙比甲少多少
<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>