* inseamna barat
ab* :ba* =3 si rest a+b
ab*=10a+b
ba*=10b+a
a,b ∈{1,2,3,4,5,6,7,8,9}
a+b<10b+a
D= IxC+R
ab*=3 x(ba*)+(a+b)
10a+b=3(10b+a)+(a+b)
10a+b=30b+3a+a+b
10a+b=31b+4a
6a=30b
a=5b
singurul numere naturale care satisfac consitia sunt a=5 si b=1.
51 :15 = 3 si rest 6
