The cafeteria bought a bag of rice, used it on the first day (3/10), used 10 kilograms on the second day, and shared this bag of rice in two days (2/5), how many kilograms is this bag of rice?
食堂买来一袋大米，第一天用了(3/10)，第二天用了10千克，两天共用去这袋大米的(2/5)，这袋大米有多少千克？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/5) - (3/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">10 / (1/10)</gadget>
<output>100</output>

<result>100</result>