In the ratio, the former term is enlarged by 4 times, and the latter term should be divided by how much to keep the ratio constant.
在比中，前项扩大4倍，要使比值不变，后项应除以多少．
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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