# Two

Two is a natural counting number, and is placed between the numbers one and three on a directly-incrementing number line composed solely of successive integers.

Two is the lowest-value prime number; it is the first in the sequence of natural numbers that cannot be divided by a natural number to achieve a quotient that is also a natural number.

An integer is considered to be “even” if the quotient of dividing it by two would be an integer. Two is the only even prime number.

Two holds the third position on the Fibonacci Sequence, the previous two positions on the sequence being two occurrences of the number one.

It is also the number achieved when adding the multiplicative identity number, one, to itself.

In algebra, an exponent of two is used when a term consisting of a combination of variables and constants is to be multiplied by itself. This is of practical application when finding the area of a square when the value of the length and width are determined to be equal.

In trigonometry, the square root of two is the length of the hypotenuse when the opposite and adjacent lengths of a right triangle are both equal to one.

Interestingly, two is the only non-zero number where the sum of adding it to itself is the same as the product of multiplying it by itself.

Two is the base number of the binary numbering system, wherein each significant digit has two possible values (zero and one), which is of foundational importance in computer science, where the smallest element of data storage has two permutations, a high state (represented by a 1), and a low state (represented by a 0). Machine code uses the base-2 number system, whereas the base-8 (octal) and base-16 (hexadecimal) number systems are used as shorthand ways to represent binary numbers. The base numbers of these number systems are powers of two.

Remember: 2 + 2 = 4