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# What are the 25 prime numbers between 1 and 100?

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The first 25 prime numbers are two, three, five, seven, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97. A prime number is a positive value only divisible by itself and the number one. For instance, the number 11 has two factors: one and 11.

## Keep Learning

Greek mathematicians studied prime numbers as far back as 300 BCE when Euclid published a series of theorems in his treatise "Elements." Euclid's work demonstrated that all non-prime numbers, or composites, are made up of a unique combination of prime numbers. In other words, a series of prime numbers can be multiplied to produce each composite number. For example, 2 x 3 = 6, and 2 x 2 x 3 = 12.

Mathematician Eratosthenes designed a rudimentary algorithm in 200 BCE that used a grid system to quickly sort out divisible numbers. The series of prime numbers is considered infinite, and as of May 2013, the largest one discovered contained 17,425,170 digits.

In modern society, prime numbers are used for security encryption, especially in banking and Internet commerce. Large composite numbers are difficult to break down to individual factors, creating a time-consuming roadblock for codebreakers.

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## Related Questions

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Digits are symbols in combinations to represent numerals, and numerals represent ideas of numbers. This is similar to how letters are symbols in combination to represent words, and words represent ideas of things. Aside from its primary purpose, digits are also studied in the field of number theory.

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Rounding to two decimal places means leaving only two numbers to the right of the decimal point. When the number in the third decimal place is any number between zero and four, round to two decimal places by deleting everything to the right of the second number. If the number in the third decimal place is any number from five to nine, round the number in the second decimal place up by one, and delete all the numbers after it.

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Two fun facts about the number two are that it is the only even prime number and its root is an irrational number. All numbers that can only be divided by themselves and by 1 are classified as prime.