math_celebrity Administrator Staff member Dec 15, 2023 #1 2 rules. If either of them passes, then the number is divisible by 11: Sum of the odd digits - Sum of the even digits is divisible by 11 Sum of the odd digits - Sum of the even digits = 0 (Ex. 121)

2 rules. If either of them passes, then the number is divisible by 11: Sum of the odd digits - Sum of the even digits is divisible by 11 Sum of the odd digits - Sum of the even digits = 0 (Ex. 121)