The students divided a piece of colored paper into 10 parts on average. It was used to fold the airplane (3/10), and it was used to fold the boat (4/10). What fraction is left?
同学们把一张彩纸平均分成10份，折飞机用了(3/10)，折小船用了(4/10)，还剩几分之几？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (3/10) - (2/5)</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>