Is 73 a Prime Number
2026-02-28 11:38 Diff
https://brightchamps.com/en-us/math/numbers/is-73-a-prime-number

A Greek mathematician, Eratosthenes found a very interesting and easy method to find out prime numbers. It is called “The Sieve of Eratosthenes”. This chart will give you a better understanding of the prime numbers.

Step 1: Firstly, determine the range of numbers to check.

To use the Sieve of Eratosthenes, we first find the square root of 73. The square root of 73 is approximately 8.5, so we need to find all prime numbers up to 8. The prime numbers that are less than or equal to 8 are 2, 3, 5, or 7.

Step 2: Use the Sieve of Eratosthenes method 

Start with a list of numbers from 2 to 73. Like 2, 3, 4,5, 6, 7, 8, 9,.......,73.

We begin the process of eliminating non-prime numbers using the Sieve of Eratosthenes. In this method, we systematically remove all composite numbers by eliminating multiples of each prime number. 

Eliminate multiples of 2, starting with 4, 6, 8, 10, 12, and so on. Continue eliminating the multiples of 2. 

Eliminate multiples of 3, starting with 6, 9, 12, 15, and so on.

Eliminate multiples of 5, starting with 10, 15, 20, 25, and so on.

Eliminate multiples of 7, starting with 14, 21, 28, 35, and so on.

  After performing these steps, the remaining numbers in the list will be the primes less than or equal to 73: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71.

Step 4: Check if 73 is in the list of primes

The number 73 appears in the list of primes, which means it is not eliminated in the Sieve of Eratosthenes.

Step 5: Since 73 is not divisible by any prime numbers less than or equal to 8, and it remains in the list of primes, 73 is a prime number.