Characteristics of numbers divisible by 3 7 9 11

Characteristics of numbers divisible by 3 7 9 11

1. The characteristics that can be divided by 3: if the sum of all digits of a number is a multiple of 3, the number can be divided by 3. For example: 111; 1 + 1 + 1 = 3, so 111 can be divided by 3; 2. The characteristics that can be divided by 7: the difference between the last three digits and the first few digits of a number (note, here should be large number minus decimal) is a multiple of 7, the number can be divided by 3