20 students line up to do exercises, and the distance between each two is 1.8 meters. How many meters is the total length of this team from front to back?
20个同学排成一队做操，每两人之间相距1.8米，这支队伍从前到后一共长多少米．
<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">19 * 1.8</gadget>
<output>34.2</output>

<result>34.2</result>