divisibility rule for 11

Rule:
A number is divisible by 11,if the difference of the sum of its digits at odd places and sum of its digits at the even places, is either 0 or a number divisible by 11 .
Example 1:
Is 567897 divisible by 11?
Solution:
The sum of the digits at odd places in the number 567897 is 5+7+9=21->I.
The sum of the digits at even places in the number 567897 is 6+8+7=21->II.
Difference of I and II is 21-21=0.
According to the rule given above,the number 567897 is divisible by 11.
Example 2:
Is 782346 divisible by 11?
Solution:
The sum of the digits at odd places in the number 782346 is 7+2+4=13->I.
The sum of the digits at even places in the number 782346 is 8+3+6=17->II.
Difference of I and II is 17-13=4.
According to the rule given above,the number 782346 is not divisible by 11.