If (1/10) of the oil in barrel A is poured into barrel B, the weight of the two barrels will be equal. It turns out that barrel B is equal to barrel A
把甲桶油的(1/10)倒入乙桶，则两桶油的重量相等．原来乙桶是甲桶的多少
<gadget id="calculator">1 / 10</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/10) * 2</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

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