A bag of rice is used up (2/5) for the first time, and the second time is 18 kg less than the first time. At this time, there is still 38 kg of rice in the bag. How much does the bag of rice originally weigh?
一袋大米，第一次用去了(2/5)，第二次的比第一次的少18千克，这时袋里还有大米38千克，这袋大米原来重多少千克？
<gadget id="calculator">38 - 18</gadget>
<output>20</output>

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

<gadget id="calculator">(2/5) + (2/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 - (4/5)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / (1/5)</gadget>
<output>100</output>

<result>100</result>