# Exploring Prime Numbers: Definition, Chart, Examples

A prime number is a positive integer greater than 1 that is only divisible by 1 and itself. Some examples of prime numbers include 2,3,5,7,11and so on. Numbers that have more than two factors are called composite numbers. The number 1 is neither prime nor composite since it has only one factor. Prime numbers are the building blocks of all other numbers, as every composite number can be factored into prime numbers. Join **WuKong Education **to explore this article about prime numbers!

## Prime Numbers List

There are several prime numbers in the number system. As we know, the prime numbers are the numbers that have only two factors, i.e. 1 and the number itself. The list of prime numbers 1 to 100 are given below:

List of Numbers | Prime Numbers |

Between 1 and 10 | 2, 3, 5, 7 |

Between 11 and 20 | 11, 13, 17, 19 |

Between 21 and 30 | 23, 29 |

Between 31 and 40 | 31, 37 |

Between 41 and 50 | 41, 43, 47 |

Between 51 and 100 | 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 |

The list also includes prime numbers 1 to 1000 and the largest known prime number as of now. Knowing these lists of prime numbers is helpful in problems involving prime factorization and other number theory questions.

## How to Find Prime Numbers

One of the most famous methods to identify prime numbers is the Sieve of Eratosthenes. In this sieve approach of how to find Prime Numbers, first we write down all natural numbers from 2 to n. Then we repeatedly cross out numbers in the list that are multiples of each prime number, starting from 2. This process filters out all composite numbers, leaving us with only the prime numbers.

An alternate formulaic method is using the formula 6n±1. We can write every prime number except 2 and 3 as 6n±1, where n is a natural number. For example, 5=6(1)-1 and 7=6(1)+1. Another strategy is using divisibility rules to quickly check if a number is divisible by 2, 3, 5, 7 or 11, which are the first few prime numbers.

Solving practical examples is also helpful for verifying prime numbers up to a certain value. Computational efficiency increases with modular arithmetic approaches.

## Prime Numbers Chart

A chart of prime numbers is a visualization of primes up to a specified value, often with multiples crossed out sequentially. The prime numbers chart, also called the Eratosthenes sieve, filters out composite numbers in an orderly manner. It demonstrates prime patterns and the decreasing frequency of primes as values increase.

Knowing prime number patterns helps solve problems more intuitively. The chart also served as an early numerical table before calculators. It plays a significant role in history by aiding the development of prime number theory. Even today, the prime number chart finds application in number theory tutorials and mathematical recreations. Its simplicity makes the underlying prime number concept easy to understand visually.

## Properties of Prime Numbers

Prime numbers have unique characteristics that distinguish them from other integers. Understanding these properties aids in solving diverse number theory problems:

- Prime numbers are natural numbers greater than 1 that are only divisible by 1 and themselves.
- Any two prime numbers are always co-prime to each other, meaning they share no common factor other than 1.
- A composite number can be expressed as a product of prime factors in only one unique way, unlike prime numbers.
- Mersenne primes take the form 2n – 1, where n itself is a prime number. Fermat primes follow the pattern 22n + 1.
- Twin prime numbers differ by 2. They demonstrate how close together primes may occasionally be found.
- The Sieve of Eratosthenes provides an iterative way to systematically list all primes up to any value using divisibility rules.
- Except for 2, all other prime numbers are odd. 2 is the only even prime number.
- Prime numbers have intriguing connections to theorems like Bertrand’s postulate and the prime number theorem regarding their asymptotic distributions.

## Examples of Prime Numbers

Let’s look at some examples to get more practice with prime numbers:

Check if 17 is a prime number.

17 is only divisible by 1 and 17. Hence, it is a prime number.

Find the prime factors of 144.

The prime factors of 144 are 2, 2, 2, 3, 3.

Are 35 and 51 co-prime numbers?

The greatest common divisor of 35 and 51 is 1. Hence, they are co-prime numbers.

Write the first ten prime numbers.

The first ten prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29.

Solving such examples of prime numbers helps test the understanding of prime number concepts like unique Prime numbers and factors, co-primality, prime factorization and more. With regular practice, one can master prime number problems.

## WuKong Math Advanced Course

For learners seeking to take their prime number knowledge beyond the basics, WuKong Learning offers an advanced online course. The **WuKong Math Advanced Course** delves deep into number theory, focusing majorly on prime numbers and related topics.

Taught live by expert tutors, the course structure follows a structured curriculum with over 50 hours of interactive lessons. Weekly assignments and quizzes help track progress. Students gain mastery over prime number formulas, properties, advanced factorization techniques and their application to cryptography.

## FAQs about Prime Numbers

### Q1. Why does the density of prime numbers decrease as numbers increase?

As numbers get larger, they have more opportunities to be divisible by primes. The prime number theorem quantifies this – the probability that a random number n is prime is about 1/ln(n). So the number of primes gradually decreases, following an inverse logarithmic pattern.

### Q2. Is there a formula to generate prime numbers?

While there is no simple formula, some patterns have been observed – almost all primes can be written in the form 6k ±1, with some exceptions like multiples of 3 or 5. Also, numbers of the form k^2 + k + c (where c is a small constant) tend to be prime. But there is no universally agreed single formula to exhaustively generate all primes.

### Q3. What is a Cunningham chain of prime numbers?

A Cunningham chain is a sequence of prime numbers where each term is obtained by adding or subtracting the digit sum of the preceding term to/from it. Example: 11, 7, 13, 10, 16, 15, 17 is a Cunningham chain. They demonstrate intricate connections between prime patterns and decimal properties.

# Conclusion

For learners seeking to elevate their prime number skills to an expert level, the WuKong Math Advanced Course presents a comprehensive online program. By delving deep into advanced topics like unique prime factorization and number theory applications, the course can help participants breakthrough to the frontiers of mathematical thought. If you wish to transform your initial prime number fascination into expert-level expertise, registering for the WuKong Math Advanced Course is a stepping stone worth considering. Contact a course advisor today to learn more about the program and how it can accelerate your proficiency with prime numbers.

Delvair holds a degree in Physics from the Federal University of Maranhão, Brazil. With over six years of experience, she specializes in teaching mathematics, with a particular emphasis on Math Kangaroo competitions. She firmly believes that education is the cornerstone of society’s future. Additionally, she holds the conviction that every child can learn given the right environment and guidance. In her spare time, she enjoys singing and tending to her plants.