8G Is it possible to tell if a whole number is divisible by

8G Is it possible to tell if a whole number is divisible by 3 just by checking its last digit? Investigate this question by considering a number of examples. State your conclusion.

Solution

Solution:
If sum of all digit of given whole number is divisible by 3,then the no. also divisible by 3.

For example
123 = 1+2+3 = 6 ÷3 =2
Hence this no. is divisible by 3.

But,just by checking its last digit it is not possible to determine that the given no. is divisible by 3 or not.
For example-
1) 169
In this given number,Last digit is 9 and it is divisible by 3.But this whole no. is not divisible by 3.So,we can not determine the divisibility of any whole no. by 3 just by checking last digit.