Make a factor tree for $21$. Do not use $1$ as a factor.

Make a factor tree for $40$. Do not use $1$ as a factor.

Make a factor tree for $48$. Do not use $1$ as a factor.

Make a factor tree for $50$. Do not use $1$ as a factor.

Find the factors of $6$ and $8$. Write the common factors in the shaded part.

Find the factors of $10$ and $14$. Write the common factors in the shaded part.

Find the factors of $18, 21$ and write the common factors in the shaded part.

Find the common factors of $18,15$.

Find the common factors of $12, 4$.