Question

What is the divisibility rule for$3$ and $9$?

Answer 1

Divisibility rule for$3$ and $9$.

• Divisibility rule for$3$:If the sum of its digits is divisible by $3$ then number is completely divisible by $3$. For example: $243$ is completely divisible by$3$ because sum of it's digits is $2+4+3=9$ which is divisible by $3$
• Divisibility rule for $9$: If the sum of its digits is divisible by $9$ then number is completely divisible by $9$.For example: $189$ is completely divisible by $9$ because sum of it's digits is $1+8+9=18=1+8=9$ which is divisible by $9$

Thus, the divisibility rule for$3$ and $9$ is that the sum of its digits is divisible by$3$ ,$9$.