Xiao Ming’s family bought a bag of rice. He ate 20% of the total for the first time, and 1/3 of the total after eating 7 kg for the second time. How much does this bag of rice weigh?
小明家买来一袋大米，第一次吃了总数的20%，第二次吃了7千克还剩总数的(1/3)没吃，这袋大米重多少千克？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/5) - (1/3)</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">7 / (7/15)</gadget>
<output>15</output>

<result>15</result>