Subtract 5 from the former item of 10:27, how much ratio must be subtracted from the latter item, how much can be subtracted unchanged
把10：27的前项减去5，后项必须减去多少比值可以不变减去多少
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">27 * (1/2)</gadget>
<output>27/2 = around 13.5</output>

<gadget id="calculator">27 - (27/2)</gadget>
<output>27/2 = around 13.5</output>

<result>27/2 = around 13.5</result>