Divisibility rules
A number is divisible by three if digits in the number add to the multiple of three.
eg: 7413 7+4+1+3=15. 15 is a multiple of three therefore 7413 is divisible by three.
A number is divisible by six if it adds to a multiple of three and is even.
Eg: 7362 7+3+6+2=18. 18 is a multiple of 3 and 6 and is even therefore 7362 is divisible by 6.
A number is divisible by 9 the digits will add to a multiple of 9.
Eg: 78534 7+8+5+3+4=27. 27 is a multiple of 9 therefore 78534 is divisible by 9.
