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Children

Answer :

There are a good many different solutions to this puzzle. 
Any contiguous pair, except 7-8, may be moved first, and after the first move there are variations. 
The following solution shows the position from the start right through each successive move to the end:

. . 1 2 3 4 5 6 7 8
4 3 1 2 . . 5 6 7 8
4 3 1 2 7 6 5 . . 8
4 3 1 2 7 . . 5 6 8
4 . . 2 7 1 3 5 6 8
4 8 6 2 7 1 3 5 . .






Math Genius