Students plant trees by the river. The river bank is 56 meters long. A tree is planted every 4 meters. Both ends must be planted. How many trees are needed in total?
同学们到河边种树，河岸长56米，每隔4米种一棵树，两端都要种，共需要多少棵树？
<gadget id="calculator">56 / 4</gadget>
<output>14</output>

<gadget id="calculator">14 + 1</gadget>
<output>15</output>

<result>15</result>