The older sister is taller than the younger sister (4/5), that is, how much shorter the younger sister is than the older sister
姐姐比妹妹高(4/5)，也就是妹妹比姐姐矮多少
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 + (4/5)</gadget>
<output>9/5 = around 1.8</output>

<gadget id="calculator">(4/5) / (9/5)</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>