<s>[INST] A positive integer is divisible by 3 if and only if the sum of its digit is a multiple of 3. Prove it. 
Statement 1 : If a positive integer is divisible by 3, then the sum of its digit is a multiple of 3. 
Statement 2 : If the sum of the digits of a positive integer is a multiple of 3, then the positive integer is divisible by 3. 

Note : The proof of both the statement should be different. 

Can we prove it using induction?[/INST]