1: 10 9 8 7 6 5 4 3 2 1 2: 10 9 8 7 6 5 4 3 2 1 3: 1 plus 2 is 3 4: 1 2 3 4 5 6 7 8 9 10 5: 10 9 8 7 6 5 4 3 2 1