20% of a barrel of oil is used, and there are 32 kilograms left. How many kilograms of this barrel of oil are there?
一桶油，用去20%，还剩32千克，这桶油原有多少千克？
<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">32 / (4/5)</gadget>
<output>40</output>

<result>40</result>