The worker uncle erected a telephone pole every 80 meters from the beginning to the end of the road, and exactly 9 poles were erected. Do you know how long this road is?
工人叔叔在公路的一侧从头到尾每隔80米立一根电线杆，刚好立了9根．你知道这段公路长多少米吗？
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">8 * 80</gadget>
<output>640</output>

<result>640</result>