During the 11th Golden Week, Mingming and his father climbed Mount Meng. They walked 5.67 kilometers up the mountain, and took 0.8 kilometers down the mountain than up the mountain. How many miles did they walk in total?
十一黄金周，明明和爸爸登蒙山．他们上山走了5.67千米，下山比上山夺走了0.8千米．他们一共走了多少千米？
<gadget id="calculator">5.67 + 0.8</gadget>
<output>6.47</output>

<gadget id="calculator">5.67 + 6.47</gadget>
<output>12.14</output>

<result>12.14</result>