To build a road, the whole road is repaired on the first day (2/15), and the whole road is repaired on the second day (3/10), what fraction of the whole road is left unrepaired?
修一条路，第一天修了全程的(2/15)，第二天修了全程的(3/10)，还剩下全程的几分之几没有修？
<gadget id="calculator">2 / 15</gadget>
<output>2/15 = around 0.133333</output>

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

<gadget id="calculator">1 - (2/15) - (3/10)</gadget>
<output>17/30 = around 0.566667</output>

<result>17/30 = around 0.566667</result>