Question

how many four digit integers n are there such that n is divisible by 9, (n-1) is divisible by 11 and (n+1) is divisible by 7​

Answer 1

answer :

hence the smallest four digit number divisible by 9 is 1008

Answer 2

We are going to use the formula of divisibility rule of 9, which is:

A number is divisible by 9, if and only if the sum of the digits of the number is divisible by 9.  

Sum of digits of 1008 = 9 (divisible)

Hence, the smallest 4-digit number divisible by 9 is 1008.