Ab + bc + ca = 77
(10a+b) +(10b+c) +(10c+a)
11a+11b+11c=77
a+b+c=77:11
a+b+c=7
ab+bc+ca=121
(10a+b) +(10b+c) +(10c+a) =121
11a+11b+11c=121
a+b+c=121:11
a+b+c=11
abc+cab+bca=444
(100a+10b+c) +(100c+10a+b) +(100b+10c+a)
111a+111b+111c=444
a+b+c=4
ab+ac+ba+bc+ca+cb=154
(10a+b) +(10a+c) +(10b+a) +(10b+c) +(10c+a) +(10c+b)
22a+22b+22c=154
a+b+c=154:22
a+b+c=7
