Multiples and Factors

Which of these is NOT a factor of $20$?

Common factors of $12$ and $15$ are ________.

The factors of $22$ are $1, 2, 11,$ and ________.

What is the LCM of $9$ and $6$?

Find the difference between the fourth multiple of $5$ and the second multiple of $5$.

Which number is a common multiple of $10$ and $20$?

What number is at the top of a factor tree that has final prime branches of $2$ and $13$?

If a factor tree for $34$ has $2$ as one branch, what is the other branch?

In a factor tree for $80$, if the branches are $8$ and $10$, what are the prime factors of $10$?

Which of these is a factor of both $16$ and $24$?

What is the $3^{rd}$ multiple of $12$?

Find the HCF of $30$ and $45$.