The garden workers planted a tree every 6 meters on both sides of the 120-meter-long road (both ends are planted), and now it is changed to plant a tree every 4 meters, so how many trees do not need to be transplanted?
园林工人在长120米的公路两侧每隔6米栽一棵树(首尾都栽)，现在改成每隔4米栽一棵树，那么不用移栽的树有多少棵？
<gadget id="calculator">120 / 12</gadget>
<output>10</output>

<gadget id="calculator">10 + 1</gadget>
<output>11</output>

<gadget id="calculator">11 * 2</gadget>
<output>22</output>

<result>22</result>