The teacher assigned a total of 10 calculation problems. Li Ming did it in the self-study class (4/10) and after school (5/10). How much of it is left?
老师布置的计算题共有10道，李明在自习课做了(4/10)，放学后做了(5/10)，还剩几分之几没有完成？
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/5) + (1/2)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">1 - (9/10)</gadget>
<output>1/10 = around 0.1</output>

<result>1/10 = around 0.1</result>