Common fractions are expressed with hyphenated words, whether the fraction is used as an adjective or a noun. Mixed fractions are typically expressed in numerals.
Only three-fourths of the patients studied developed symptoms.
Only one-half the normal dose was given.
In some cases, fractions can be expressed with an indefinite article preceding the denominator. Do not use the hyphen with this type of construction.
The study was terminated after half an hour.
Fractions are hyphenated when they are used as adjectives; do not hyphenate fractions used as nouns or objects of a prepositional phrase.
one-half normal strength (adjective)
proximal one-third of the forearm (noun phrase)
The patient was advised to cut the pills in half (object of preposition)
A quarter may be used in place of one-fourth.
A quarter of the patients studied developed the predicted symptoms.
Â Use the numeric fraction when the measurement forms a compound modifier preceding a noun.
A 1/4-inch incision was made.
The 3/4-pound lesion was removed.
For less precise measurements, mixed fractions may be used instead of decimals. These are typically measures of time or nonmetric measurements.
The surgery lasted 6½ hours.
The laceration measured 1¼ inches.
The patient was n.p.o. for 3½ days.
D: The patient walks one and a half miles a day.
T: The patient walks 1-1/2 miles a day OR The patient walks 1½ miles a day.
Fractions dictated with a decimal point
If a fraction is dictated as a decimal point, use the decimal form.
D: The scar measures 2-point-3 inches in length.
T: The scar measures 2.3 inches in length