There are 25 prime numbers between 1 to 100.

The prime numbers between 1 to 100 are as follows:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97.

What is a prime number?
A prime number is a positive integer greater than 1 that has no positive divisors other than 1 and itself.

How to find if a number is prime or not?
Simply, if the number is n, we can divide the given number with a range from 2 to n-1 and if any number in the range perfectly divides n, then it is not a prime otherwise it is a prime.