Ok so from AA3+2=AAA we know that 3+2=A, therefore A=5.
From CC6+6=CBB, we know that 6+6=12 therefore the last digit of the number must be 2, so B=2. Also, we know that the tens place goes up by one if 6 is added to 6, therefore B is one greater than C, therefore C=2-1 which is 1. So, ABC= 521
