Look up one half in Wiktionary, the free dictionary.
Natural number
← −0.5
0.5
1.5 →
−1 0 1 2 3 4 5 6 7 8 9 → List of numbersIntegers← 0 10 20 30 40 50 60 70 80 90 →Cardinalone halfOrdinal1⁄2th (halfth)Binary0.12Ternary0.11111111113Senary0.36Octal0.48Duodecimal0.612Hexadecimal0.816Greek∠Roman numeralsSEgyptian hieroglyph𓐛HebrewחֵצִMalayalam൴Chinese半Tibetan༪
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One half is the multiplicative inverse of 2. It is an irreducible fraction with a numerator of 1 and a denominator of 2. It often appears in mathematical equations, recipes and measurements.
As a word[edit]One half is one of the few fractions which are commonly expressed in natural languages by suppletion rather than regular derivation. In English, for example, compare the compound "one half" with other regular formations like "one-sixth".
A half can also be said to be one part of something divided into two equal parts. It is acceptable to write one half as a hyphenated word, one-half.
Mathematics[edit]One half is the rational number that lies midway between 0 and 1 on the number line. 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".
A square of side length one, here dissected into rectangles whose areas are successive powers of one half.
A number raised to the power of one half is equal to its square root. This follows from the fact that when multiplying powers, the exponents add. So, a 1 / 2 {\displaystyle a^{1/2}} times itself is a 1 / 2 + 1 / 2 {\displaystyle a^{1/2+1/2}} which is a 1 {\displaystyle a^{1}} , which equals a {\displaystyle a} .
times itself is
a
1
/
2
+
1
/
2
{\displaystyle a^{1/2+1/2}}
which is
a
1
{\displaystyle a^{1}}
, which equals
a
{\displaystyle a}
.
The area of a triangle is one half its base and its height, also known as its altitude.[1]
Fundamental region of the modular j-invariant in the upper half-plane (shaded gray), with modular discriminant
|
τ
|
≥
1
{\displaystyle |\tau |\geq 1}
and
−
1
2
and
−
1
2