There is a bag of rice, 40% of which was eaten in the first week, and 12 kg in the second week, leaving 6 kg. How many kilograms does this bag of rice originally weigh?
有一袋大米，第一周吃了40%，第二周吃了12千克，还剩6千克．这袋大米原来有多少千克？
<gadget id="calculator">12 + 6</gadget>
<output>18</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">18 / (3/5)</gadget>
<output>30</output>

<result>30</result>