Răspuns:
abc:bc=5 rest4
abc=5bc+4
100a+bc=5bc+4
100a=5bc-bc +4
100a=4bc+4 impartim la 4
20a=bc+1=>c+1=10=>c=9
20a=10b+9+1
20a=10b+10
2a=b+1
ptr a=1=>2=b+1=>b=1=>nr 119
ptr a=2=>4=b+1=>b=3=>nr239
ptr a=3=>6=b+1=>b=5=>nr359
ptr a=4=>8=b+1=>b=7=>nr479
ptr a=5=>10=b+1=>b=9=>nr599
