Liying Village needs to build a 5-kilometer road. The full length (1/5) was built in the first week, and the full length (3/10) was built in the second week. What fraction of the full length is left?
李营村要修一条5千米的公路，第一周修了全长的(1/5)，第二周修了全长的(3/10)，还剩下全长的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) + (3/10)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>