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Prime Numbers Upto 100

Prime numbers up to 100 are all the prime numbers that come between 1 and 100. Any whole number which is greater than 1 and it is divisible only by 1 and the number itself, is known as a prime number. The formula of prime numbers helps in representing the general form of a prime number. Let us learn how to find out the prime numbers up to 100 by Eratosthenes’ method, and check the list of prime numbers between 1 to 100.

 1 Definition of Prime Numbers 2 How to find Prime Numbers Up to 100? 3 List of Prime Numbers Up to 100 4 FAQs on Prime Numbers Up to 100

## Definition of Prime Numbers

Prime numbers are natural numbers that have only two factors, that is, 1 and the number itself. For example, numbers like 5, 7, 13 have only two factors, so they are prime numbers. Other numbers that have more than 2 factors are called composite numbers.

It is to be noted that the number 1 is neither a prime number nor a composite number.

Important Notes

• Prime numbers are natural numbers greater than 1, that have only two factors, 1 and the number itself.
• A number can be a prime number if it is a non-zero whole number.
• Prime factorization is a method to find prime numbers.

## How to Find Prime Numbers up to 100?

We can find prime numbers in mathematics by using an ancient technique, that is, the sieve of Eratosthenes. It is an ancient method for finding all the prime numbers up to any given limit. The following steps show how to find all the prime numbers up to 100 by Eratosthenes’ method. Leave the number 1 as all prime numbers are greater than one.

• Step 1: First create a list of numbers from 2 to 100 as shown in the figure given below.
• Step 2: Ignore the number 1 and start from 2. The number 2 is the first number in the list and it is a prime number too; cross out all the multiples of 2 in the list. Such as 4, 6, 8, 10, 12, 14, 16 and so on up to 100.
• Step 3: 3 is the next number in the list after 2; cross out all the multiples of 3 in the list, such as 6, 9,12, 15, 18, 21, 24 and so on up to 100.
• Step 4: 5 is the next number in the list after 3; cross out all the multiples of 5 in the list, such as 10, 15, 20, 25, 30 and so on up to 100.
• Step 5: 7 is the next number in the list after 5; the next step would be to cross out all the multiples of 7 in the list, such as 14, 21, 28, 35, 42, 49, 56, 63 and so on up to 100.
• Step 6: After this step, when all the multiples are crossed out, only the prime numbers will be left uncrossed and these are the numbers marked yellow in the following chart. These are all prime numbers up to 100.

## List of Prime Numbers Between 1 to 100

Observe the list of prime numbers up to 100 given below.

### List of Prime Numbers from 1 to 100

Prime numbers between 1 and 10

2, 3, 5, 7

Prime numbers between 11 and 20

11, 13, 17, 19

Prime numbers between 21 and 30

23, 29

Prime numbers between 31 and 40

31, 37

Prime numbers between 41 and 50

41, 43, 47

Prime numbers between 51 and 100

53, 59, 61, 67, 71, 73, 79, 83, 89, 97

So, there are total 25 prime numbers up to 100. Therefore, the prime numbers 1 to 100 can be listed as,

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.

### Even Prime Numbers from 1 to 100

Even prime numbers means prime numbers that are even. Interestingly, there is only 1 even prime number which is 2. This is because 2 is the only even number that has only 2 factors, 1 and 2. Otherwise, all even numbers have more than 2 factors. Therefore, 2 is a prime number and it is the only even prime number.

### Odd Prime Numbers from 1 to 100

Odd prime numbers are those prime numbers that are odd. We know that odd numbers are those numbers that are not divisible by 2. Therefore, odd prime numbers from 1 to 100 can be listed as follows: 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97. It should be noted that except 2, all the prime numbers are odd.

Some facts on prime numbers 1 to 100

• 2 is the only even prime number and the remaining even numbers are not prime numbers as they can be divided by 2.
• Any prime number greater than 5 and ends with a 5 can be divided by 5 so it cannot be a prime number.
• Prime numbers have exactly two factors and 0 and 1 are not prime numbers.

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## Examples on Prime Numbers 1 to 100

1. Example 1: Which of the given numbers is a prime number, 13 or 15?

Solution:

The given numbers are 13 and 15.

The factors of 15 = 1, 3, 5, 15. So, 15 has more than two factors.

The factors of 13 = 1, 13. So, 13 has exactly two factors.

We can also verify this result from the list of prime numbers 1 to 100

Therefore, the number 13 is the prime number as it has only two factors and 15 is not a prime number because it has more than two factors.

2. Example 2: Why is 18 not a prime number?

Solution:

The given number is 18.

The factors of 18 = 1, 2, 3, 6, 9, and 18. This means that 18 has more than two factors.

Since 18 has more than two factors, it is not a prime number.

We can verify this result from the list of prime numbers up to 100.

3. Example 3: Select the prime numbers from the following list: 54, 68, 97, 37

Solution:

The list of prime numbers up to 100 shows that among the given numbers, 97 and 37 are prime numbers and 54 and 68 are composite numbers.

## FAQs on Prime Numbers Up to 100

### What are the Prime Numbers from 1 to 100?

There are 25 prime numbers up to 100. These prime numbers from 1 to 100 are listed 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.

### How to Find Prime Numbers from 1 to 100?

We can find prime numbers in mathematics by using an ancient technique called the ‘Sieve of Eratosthenes’. It is an ancient method for finding all the prime numbers up to any given limit. Through this technique, we select the first number from the list of natural numbers from 2 to 100, and then we cross out all the multiples of that number except that number. then, we are left with only prime numbers. With this method, we can easily find out prime numbers up to 100. A detailed explanation of this method is given above on this page.

What is the Shortcut to find Prime numbers Up to 100?

We can apply the Sieve of Eratosthenes technique to quickly find the prime numbers 1 to 100. List down all the numbers from 2 to 100 and start selecting numbers and cancel all the multiples of that number following the suitable rules. The remaining numbers are prime numbers. A detailed explanation of this method is given above on this page.

What is the Difference Between a Prime Number and a Co-Prime Number?

A prime number is a number that has only two factors, that is, 1 and the number itself. For example, 2, 3, 5, and 7 are prime numbers. Co-prime numbers are the numbers whose Highest Common Factor (HCF) is 1. For example, 5 and 9 are co-prime numbers. Co-prime numbers can be prime numbers or composite numbers.

### Is 87 a Prime Number?

A number is called prime if it does not have any factors except 1 and itself. Here, the factors of 87 are =1, 3, 29, and 87. Hence it is a composite number. Thus, 87 is not a prime number.

### What are Twin Prime Numbers Up to 100?

Twin prime numbers are prime numbers with exactly one composite number in between them. Twin prime numbers up to 100 can be listed as, (3, 5), (5, 7), (11, 13), (17, 19), (29, 31), (41, 43), (59, 61), (71, 73).

What is the HCF of the Smallest Prime Number and the Smallest Composite Number?

Prime numbers are the numbers that have exactly two factors, that are, 1 and the number itself. The smallest prime number is 2 and the smallest composite number is 4. Therefore, the Highest Common Factor (HCF) of the smallest composite number and the smallest prime number is 2.

### List the Prime Numbers Between 1 and 100.

There are 25 prime numbers up to 100. The list of prime numbers between 1 to 100 is given 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 and 97.

### What is the only Even Prime Number?

The only even prime number is 2. This is an even number but it does not have any factors other than 1 and 2.

What are the Greatest and Least Prime Numbers from 1 to 100?

The greatest prime number from 1 to 100 is 97 and the smallest prime number between 1 and 100 is 2.

### How many Prime Numbers are there Between 1 and 100?

There are 25 prime numbers between 1 and 100. they can be listed 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 and 97.

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