Question

How many composite numbers are between $1$ and $50$?

Answer 1

Estimate the composite numbers:

Numbers that have more than only factors, that are except $1$ and the number itself is called a composite number.

We know that every even number has the factor $2$ except for the number $2$ itself.

Hence, every even number is a composite number except number $2$.

Among the odd numbers, we must look for numbers that are divisible by $3,5,7,11,13,17,19$.

Applying this points, we can enlist the composite numbers, and they are:

$4,6,8,9,10,12,14,15,16,18,20,21,22,24,25,26,27,28,30,32,33,34,35,36,38,39,40,42,44,45,46,48,49$

There are $33$ numbers in this set of numbers.

Hence, there are $33$ composite numbers are between $1$ and $50$.