12. EXAMPLE & REASONING
• 2 is not a factor because the last digit (1) is not even.
• 3 is not a factor because the sum of the digits (3 + 1 = 4) is not
divisible by 3.
• 4 is not a factor because the number formed by the last two digits
(31) is not divisible by 4.
• 5 is not a factor because the last digit (1) is not 0 or 5.
• 6 is not a factor because the number is not divisible by 2 and 3.
• 9 is not a factor because the sum of the digits (3 + 1 = 4) is not
divisible by 9.
• 10 is not a factor because the last digit (1) is not 0.