The front and back of the two buildings are 27 meters apart, and there is a cement road in the middle. Now it is necessary to plant trees on both sides of the road (both ends are planted), one tree every 3 meters, how many saplings should be prepared in total?
两幢楼前后相隔27米，中间有一条水泥路相通．现要在路两边植树(两端都种)，每隔3米植一棵，一共要准备多少棵树苗？
<gadget id="calculator">27 / 3</gadget>
<output>9</output>

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

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>