On the first day, the grain store sells (2/5) tons of rice in the morning, (1/4) tons of rice in the afternoon, and (7/10) tons of rice on the second day, and sells less on the first day than on the second day How many tons of rice?
粮店第一天上午卖出(2/5)吨大米，下午卖出(1/4)吨大米，第二天卖出(7/10)吨大米，第一天比第二天少卖出多少吨大米？
<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

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

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">(2/5) + (1/4)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">(7/10) - (13/20)</gadget>
<output>1/20 = around 0.05</output>

<result>1/20 = around 0.05</result>