A canal has been built for 17 kilometers, and the remaining 13 kilometers have not been repaired. How much of the total length is the unrepaired canal?
一条水渠已修了17千米，还剩下13千米没有修，未修的占全长的多少．
<gadget id="calculator">13 + 17</gadget>
<output>30</output>

<gadget id="calculator">13 / 30</gadget>
<output>13/30 = around 0.433333</output>

<result>13/30 = around 0.433333</result>