ab = 10a + b
ba = 10b + a
ab-ba=9a-9b = 45
a - b = 5
a=6; b=1
a=7; b=2
a=8; b=3
a=9; b=4
61; 72; 83; 94
ab = 10a + b
ba = 10b + a
ab-ba=9a-9b = 45
a - b = 5
a=6; b=1
a=7; b=2
a=8; b=3
a=9; b=4
61; 72; 83; 94