Question

Write the converse and contrapositive of each of the following:
If a positive integer $n$ is divisible by $9$, then the sum of its digits is divisible by $9$

Answer 1

Converse: If the sum of the digits of a positive integer $n$ is not divisible by $9$, then it is divisible by $9$.

Contrapositive: If the sum of teh digits of a positive integer $n$ is not divisible by $9$, then it is not divisible by $9$, then it is not divisible by $9$.