A tree is 24 meters high, and there is a snail under the tree trying to climb from the bottom to the top of the tree. It climbs up 6 meters during the day and slides down 4 meters at night. How many days does it take for this snail to climb to the top of a tree?
一棵树高24米，树底下有一只蜗牛想从树底爬到树顶．它白天向上爬6米，晚上向下滑4米，这只蜗牛经过多少天可以爬上树顶．
<gadget id="calculator">24 - 6</gadget>
<output>18</output>

<gadget id="calculator">6 - 4</gadget>
<output>2</output>

<gadget id="calculator">18 / 2</gadget>
<output>9</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<result>10</result>