Find the common factors of the numbers :

$45$ and $81$

Find first three common multiples of the numbers.

$6$ and $8$

Find first three common multiples of the numbers.

$10$ and $15$

Find first three common multiples of the numbers.

$4$ and $6$

Find first three common multiples of the numbers.

$12$ and $16$

Find out by what greatest number the given numbers are divisible:

$12,22$

Find out by what greatest number the following numbers is divisible:

$20,35$

Find out by what greatest number the given number is divisible.

$45,81$

Find out by what greatest number, the numbers $64$ and $56$ are divisible.