When we write $212$ as a product of prime factors, we get $2\times 2\times a$. Write the value of $a$ in the answer box.

When we write $364$ as a product of prime factors, we get $2\times 2\times 7\times a$. Write the value of $a$ in the answer box.

When we write $540$ as a product of prime factors, we get $2\times 2\times 3\times 3\times 3\times \mathrm{a}$. Write the value of $a$ in the answer box.

Find the HCF using the prime factorisation method.
$216$ and $630$

Find the HCF of $16, 24$ and $85$ using the prime factorization method.

Find the HCF using the prime factorization method.

$48$ and $120$

Find the HCF using the division method.

$12$ and $48$

Find the HCF using the division method.

$136, 170$ and $255$

Find the HCF using the division method.

$36$ and $63$