Răspuns:
a)10a+b+10b+c+10c+a=77
11a+11b+11c=77 /:11
a+b+c=7
b)10a+b+10b+c+10c+a=121
11a+11b+11c=121 /:11
a+b+c=11
c)100a+10b+c+100c+10a+b+100b+10c+a=444
111a+111b+111c=444 /:111
a+b+c=4
d)10a+b+10a+c+10b+a+10b+c+10c+a+10c+b=154
22a+22b+22c=154 /:22
a+b+c=7
