Suppose the side length is The square tile floor with a side length of 9dm has just been laid
7|x
7, the least common multiple of 9 is 63
63|x
< p>x>=6363/7=9
63/9=7
Pave the floor with square tiles with a side length of 9dm,** *It takes 7*7=49 pieces
Pave the floor with square tiles with a side length of 7dm, ***It takes 9*9=81 pieces