Fill in the blanks to make the statements true.

A number is divisible by 11 if the differences between the sum of digits at its odd places and that of digits at the even places is either 0 or divisible by ………….. .


Let abcd be a four-digit number.


The digits at odd places are a and c, even places are b and d. (a + c)-(b + d) = 0.


It also follows that (a + c) – (b + d) should be divisible by 11 if (a + c)-(b + d)≠0.


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