10 1 2 3 4 5 6 7 8 9 -> 10 21 2 3 4 5 -> 6 310 9 8 7 6 5 4 3 2 1 0 -> -1 45 10 15 20 -> 25 53 6 9 12 15 18 21 24 27 -> 30 60 71 82 93 10