A is 5 times that of B, and how much less is B than A.
甲是乙的5倍，乙比甲少多少．
<gadget id="calculator">1 * 5</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

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