Happy Village builds a road. The road was repaired in the first month (3/10), and the road was repaired in the second month (1/4). What percentage of the road remained unrepaired?
幸福村修一条路．第一个月修了这条路的(3/10)，第二个月修了这条路的(1/4)，还剩这条路的几分之几没有修？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

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

<gadget id="calculator">1 - (3/10) - (1/4)</gadget>
<output>9/20 = around 0.45</output>

<result>9/20 = around 0.45</result>