Question

What is the divisibility rule of 99

Answer 1

For a number to be divisible by 99, the given number has to be divisible by 9 and 11.

Answer 2

For a number to be divisible by 99, the given number has to be divisible by 9 and 11, both of which are simple tests.
Divisible by 9 test. If sum of digits is divisible by 9 then the number is divisible by 9.
Divisible by 11 test. If sum of ODD positioned digits minus the sum of the EVEN positioned digits is divisible by 11 then the number is divisible by 11.