There is a bag of rice in the cafeteria. I ate 20% of it in the first week, and I ate 10 kilograms less in the second week than in the first week. At this time, there are 100 kilograms left. How many kilograms of this bag of rice are there?
食堂有一袋大米，第一周吃了20%，第二周比第一周少吃10千克，这时还剩100千克，这袋大米原有多少千克？
<gadget id="calculator">100 - 10</gadget>
<output>90</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5) - (1/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">90 / (3/5)</gadget>
<output>150</output>

<result>150</result>