Divisibility by three and nine

This task is about whether numbers are divisible by three or by nine.
Answer the following question without using a calculator.

 

a)
i)
 
 Is 25,396 exactly divisible by 3?                       YES /  NO     (circle one)
 
ii)
Explain how you could decide this without having to do the division.
 

 
 
 
 
 
 
 

 
 
b)
 
i)
 
Is 4,776 exactly divisible by 9?                         YES /  NO     (circle one)
 
ii)
Explain how you could decide this without having to do the division.