有一排电线杆，每相邻两根间的距离是45cm，现在要改成60cm，如果起点的那根不动，再隔多远又有一根电线杆不必移动？

数学题解答：从起点的电线杆到不必移动的电线杆的距离应是45和60的最小公倍数。

算出45和60的最小公倍数即可知距离是多少米，这里需要用到分解质因数的方法。

45＝3×3×5，60＝2×2×3×5

3×5×3×2×2＝180

答：再隔180米又有一根电线杆不必移动。

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