columns. Not counting: 20% of a bag of rice is used, and there are 50 kilograms left. How many kilograms of this bag of rice are there?
列式．不计算：一袋米，用去20%，还剩50公斤，这袋米原有多少公斤？
<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">50 / (4/5)</gadget>
<output>125/2 = around 62.5</output>

<result>125/2 = around 62.5</result>