# Understanding Integers

So, what are integers? An integer is simply a number. It can be a negative number or a positive number, e.g. 2, -3, +4. All whole numbers are integers. Decimals and fractions cannot be integers.

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In mathematics, integers are a set of numbers that include positive numbers, negative numbers, and zero. They can be represented on a number line that extends infinitely in both positive and negative directions. Integers are often denoted by the symbol “Z”, which stands for the German word “Zahlen”, meaning “numbers”.

Integers are used in a wide range of mathematical operations, including addition, subtraction, multiplication, and division. When adding integers, the sum will either be positive, negative, or zero, depending on the signs of the numbers being added. Similarly, when subtracting integers, the difference will also have a positive, negative, or zero result. Multiplication and division of integers can be more complex, especially when dealing with negative numbers, but they are also fundamental operations that are used in many mathematical applications.

One important property of integers is divisibility. A number is said to be divisible by another number if it can be divided by that number without leaving a remainder. For example, 6 is divisible by 3, because 6 divided by 3 is 2 with no remainder. Divisibility is an important concept in number theory and is used to determine whether a number is a prime number or a composite number.

Prime numbers are integers that are only divisible by 1 and themselves. They are an important area of study in number theory and have applications in cryptography and computer science. In contrast, composite numbers are integers that are not prime and can be factored into smaller integers. The prime factorization of a composite number is the unique set of prime numbers that, when multiplied together, equal the composite number.

Integers have many real-world applications, from measuring temperature and distance, to calculating financial transactions and analyzing data. They are an essential part of mathematics and are used in a wide variety of fields, including science, engineering, and economics.