I got the same answer as Melody, but with a slightly different approach.....
Here are all the "sets" ot the positions that the "separated" children can occupy :
1 3 5 2 4 6
1 3 6 2 4 7
1 3 7 2 5 7
1 4 6 3 5 7
1 4 7
1 5 7
And for each set, the "separarted" children can be arranged in 3! ways
And for each of these arrangements, the other four children can be arranged in 4! ways in the other 4 positions.........so
10 sets * 3! arrangements of the separated set * 4! arrangements of the other children = 1440 total arrangements.......
