Gardeners plant trees on one side of a road. The distance between every two trees is 4 meters. A total of 70 trees are planted. How long is the road in meters?
园林工人在一条马路的一边栽树，每2棵树之间的距离是4米，一共栽树70棵，这条马路长多少米．
<gadget id="calculator">70 - 1</gadget>
<output>69</output>

<gadget id="calculator">4 * 69</gadget>
<output>276</output>

<result>276</result>