One canal is 17.8 meters long and the other is 5.74 meters longer. How many meters are the two canals in total?
一条水渠长17.8米，比另一条长5.74米，两条水渠一共长多少米？
<gadget id="calculator">17.8 - 5.74</gadget>
<output>12.06</output>

<gadget id="calculator">12.06 + 17.8</gadget>
<output>29.86</output>

<result>29.86</result>