Which pair of numbers has a H.C.F that is not a prime number?

The maximum number of students among whom $1001$ pens and $910$ pencils can be distributed, such that each student gets the same number of pens and same number of pencils is:

$\frac{1219}{1431}$, when reduced to its simplest form, by dividing the numerator and denominator by their H.C.F is

When teams of size are formed from three groups of $512, 430$ and $489$ students separately, $8, 10$ and $9$ respectively are left out. What could be the largest size of the team?

Challenge!

What is the H.C.F of  $4\times 27\times 3125, 8\times 9\times 25\times 7$ and  $16\times 81\times 5\times 11\times 49$.

Find the L.C.M of the following numbers by listing multiples.

$12, 16$

Find the L.C.M of the following numbers by listing multiples.

$15, 20$

Find the L.C.M of given numbers by listing multiples.

$7, 8$

Find the L.C.M of the following numbers by listing multiples.

$3, 4$ and $6$