what is the divisibility by 11

 divisibility of is so easy take a number suppose 231238 then circle the odd places then, write down

the sum of odd numbers = 2+1+3=6

the sum of even numbers = 3+2+8=13

thier differences = 13 - 6 = 7

Therefore, it is not divisible by 11

and remember: multiples of 11 are only number divisible by 11