On one side of a road, a telephone pole is erected every 6 meters from the beginning to the end, with a total of 51 poles. How long is this road in meters?
在一条公路一边从头至尾每隔6米架设一根电线杆，共用51根．这条公路全长多少米？
<gadget id="calculator">51 - 1</gadget>
<output>50</output>

<gadget id="calculator">6 * 50</gadget>
<output>300</output>

<result>300</result>