A bag of rice is 20 kilograms, 7 kilograms are eaten in the first week, and 2/5 of this bag of rice is eaten in the second week, what fraction of this bag of rice is left?
一袋大米20千克，第一周吃了7千克，第二周吃了这袋大米的(2/5)，还剩下这袋大米的几分之几？
<gadget id="calculator">7 / 20</gadget>
<output>7/20 = around 0.35</output>

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

<gadget id="calculator">1 - (7/20) - (2/5)</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>