FlexFit™ 3 Adjustable Bed Base – Sleep Number

3 (three) is a number, numeral and digit. It is the natural number following 2 and preceding 4, and is the smallest odd prime number and the only prime preceding a square number. It has religious and cultural significance in many societies.

A bed is an item of furniture that is used as a place to sleep, rest, and relax.

Most modern beds consist of a soft, cushioned mattress on a bed frame. The mattress rests either on a solid base, often wood slats, or a sprung base. Many beds include a box spring inner-sprung base, which is a large mattress-sized box containing wood and springs that provide additional support and suspension for the mattress. Beds are available in many sizes, ranging from infant-sized bassinets and cribs, to small beds for a single person or adult, to large queen and king-size beds designed for two people. While most beds are single mattresses on a fixed frame, there are other varieties, such as the murphy bed, which folds into a wall, the sofa bed, which folds out of a sofa, the trundle bed, which is stored under a low, twin-sized bed and can be rolled out to create a larger sleeping area, and the bunk bed, which provides two mattresses on two tiers as well as a ladder to access the upper tier. Temporary beds include the inflatable air mattress and the folding camp cot. Some beds contain neither a padded mattress nor a bed frame, such as the hammock. Other beds are made specifically for animals.

Beds may have a headboard for resting against, and may have side rails and footboards. "Headboard only" beds may incorporate a "dust ruffle", "bed skirt", or "valance sheet" to hide the bed frame. To support the head, a pillow made of a soft, padded material is usually placed on the top of the mattress. Some form of covering blanket is often used to insulate the sleeper, often bed sheets, a quilt, or a duvet, collectively referred to as bedding. Bedding is the removable non-furniture portion of a bed, which enables these components to be washed or aired out.

A number is a mathematical object used to count, measure, and label. The most basic examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. More universally, individual numbers can be represented by symbols, called numerals; for example, "5" is a numeral that represents the number five. As only a relatively small number of symbols can be memorized, basic numerals are commonly organized in a numeral system, which is an organized way to represent any number. The most common numeral system is the Hindu–Arabic numeral system, which allows for the representation of any non-negative integer using a combination of ten fundamental numeric symbols, called digits. In addition to their use in counting and measuring, numerals are often used for labels (as with telephone numbers), for ordering (as with serial numbers), and for codes (as with ISBNs). In common usage, a numeral is not clearly distinguished from the number that it represents.

In mathematics, the notion of number has been extended over the centuries to include zero (0), negative numbers, rational numbers such as one half ${\displaystyle \left({\tfrac {1}{2}}\right)}$, real numbers such as the square root of 2 ${\displaystyle \left({\sqrt {2}}\right)}$ and π, and complex numbers which extend the real numbers with a square root of −1 (and its combinations with real numbers by adding or subtracting its multiples). Calculations with numbers are done with arithmetical operations, the most familiar being addition, subtraction, multiplication, division, and exponentiation. Their study or usage is called arithmetic, a term which may also refer to number theory, the study of the properties of numbers.

Besides their practical uses, numbers have cultural significance throughout the world. For example, in Western society, the number 13 is often regarded as unlucky, and "a million" may signify "a lot" rather than an exact quantity. Though it is now regarded as pseudoscience, belief in a mystical significance of numbers, known as numerology, permeated ancient and medieval thought. Numerology heavily influenced the development of Greek mathematics, stimulating the investigation of many problems in number theory which are still of interest today.

During the 19th century, mathematicians began to develop many different abstractions which share certain properties of numbers, and may be seen as extending the concept. Among the first were the hypercomplex numbers, which consist of various extensions or modifications of the complex number system. In modern mathematics, number systems are considered important special examples of more general algebraic structures such as rings and fields, and the application of the term "number" is a matter of convention, without fundamental significance.

Sleep is a state of reduced mental and physical activity in which consciousness is altered and certain sensory activity is inhibited. During sleep, there is a marked decrease in muscle activity and interactions with the surrounding environment. While sleep differs from wakefulness in terms of the ability to react to stimuli, it still involves active brain patterns, making it more reactive than a coma or disorders of consciousness.

Sleep occurs in repeating periods, during which the body alternates between two distinct modes: REM and non-REM sleep. Although REM stands for "rapid eye movement", this mode of sleep has many other aspects, including virtual paralysis of the body. Dreams are a succession of images, ideas, emotions, and sensations that usually occur involuntarily in the mind during certain stages of sleep.

During sleep, most of the body's systems are in an anabolic state, helping to restore the immune, nervous, skeletal, and muscular systems; these are vital processes that maintain mood, memory, and cognitive function, and play a large role in the function of the endocrine and immune systems. The internal circadian clock promotes sleep daily at night, when it is dark. The diverse purposes and mechanisms of sleep are the subject of substantial ongoing research. Sleep is a highly conserved behavior across animal evolution, likely going back hundreds of millions of years.

Humans may suffer from various sleep disorders, including dyssomnias, such as insomnia, hypersomnia, narcolepsy, and sleep apnea; parasomnias, such as sleepwalking and rapid eye movement sleep behavior disorder; bruxism; and circadian rhythm sleep disorders. The use of artificial light has substantially altered humanity's sleep patterns. Common sources of artificial light include outdoor lighting and the screens of electronic devices such as smartphones and televisions, which emit large amounts of blue light, a form of light typically associated with daytime. This disrupts the release of the hormone melatonin needed to regulate the sleep cycle.