6.1. Mark thought of a three-digit number greater than 500 and said that if all odd digits of this number are replaced with $A$, and even digits with Б, the result would be АББ. If all digits divisible by three are replaced with В, and those not divisible by three with Г, the result would be ВВГ. List all three-digit numbers that meet these conditions.
Answer: $902,904,908,962,964,968$ (All answers)

Solution. The first digit must be divisible by 3, be odd, and not less than 5. Only the digit 9 fits. The second digit must be even and divisible by 3. The digits 0 and 6 fit. The last digit is even and does not divide by 3. The digits 2, 4, and 8 fit. Therefore, all suitable numbers are: 902, 904, 908, 962, 964, 968.