Decompose 19 into number pairs
Pairs mean the two numbers must add to 19
19 = 18 + 1
19 = 17 + 2
19 = 16 + 3
19 = 15 + 4
19 = 14 + 5
19 = 13 + 6
19 = 12 + 7
19 = 11 + 8
19 = 10 + 9
19 = 10 + 9
19 = 11 + 8
19 = 12 + 7
19 = 13 + 6
19 = 14 + 5
19 = 15 + 4
19 = 16 + 3
19 = 17 + 2
19 = 18 + 1