20% of a barrel of oil is used up, and there are 140 kilograms left. How many kilograms are there in this barrel of oil?
一桶油用去20%，还剩140千克，这桶油一共有多少千克千克．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">140 / (4/5)</gadget>
<output>175</output>

<result>175</result>