Plant trees on both sides of an 800-meter-long road, plant trees at the top and not at the bottom, and plant one tree every 5 meters. How many trees are needed in total?
在一条长800米的公路两旁种树，顶端栽、底端不栽，每隔5米栽一棵，一共需要多少棵树？
<gadget id="calculator">800 / 5</gadget>
<output>160</output>

<gadget id="calculator">160 * 2</gadget>
<output>320</output>

<result>320</result>