Dad bought a bag of rice. We ate 20% of the bag of rice in the first week, and 25 kg in the second week. At this time, there were still 55 kg left. How many kg did the bag of rice originally have?
爸爸买来一袋大米，第一周我们吃了这袋大米的20%，第二周吃了25千克，这时还剩下55千克，这袋大米原有多少千克？
<gadget id="calculator">25 + 55</gadget>
<output>80</output>

<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">80 / (4/5)</gadget>
<output>100</output>

<result>100</result>