How to find whether a large number is divisible by 3 ?

Lets consider a small number 234 is divisible by 3.



So here is a trick     2 + 3 + 4 = 9 



Since 9 is divisible by 3 



Therefore 234 is divisible by 3....



Now consider a large number  27934576592477693217



So

2 + 7 + 9 + 3 + 4 + 5 + 7 + 6 + 5 + 9 + 2 + 4 + 7 + 7 + 6 + 9 + 3 + 2 + 1 + 7 = 105



You can further add 1 + 0 + 5 = 6



As 6 is divisible by 3



Therefore 27934576592477693217 is divisible by 3...

Posted in: Division, Maths