Refrigerator
Refrigerator

One half

One half is the irreducible fraction resulting from dividing one by two (2) or the fraction resulting from dividing any number by its double. Multiplication by one half is equivalent to division by two, or halving; conversely, division by one half is equivalent to multiplication by two, or "doubling". One half appears often in mathematical equations, recipes, measurements, etc. Half can also be said to be one part of something divided into two equal parts.
One half has two different decimal expansions, the familiar 0.5 and the recurring 0.49999999... It has a similar pair of expansions in any even base. It is a common trap to believe these expressions represent distinct numbers: see the proof that 0.999... equals 1 for detailed discussion of a related case. In odd bases, one half has no terminating representation, only a single representation with a repeating fractional component, such as 0.11111111... in ternary.
One half is also one of the few fractions which is commonly expressed in natural languages by suppletion rather than regular derivation: in English, for example, compare "one half" against other regular formations like "one sixth".