State fractions in text in the simplest possible way,
usually in words or decimals. Do not combine a figure and a spelledout
number.
Generally spell out half, third, quarter:
a half or onehalf
two and a half
Spell out simple fractions unless used in pairs or in dimensions, or fractions that are cumbersome:


seveneighths
4¾ or
3½ by 4½ feet
11½

1/7000 (do not use th) of a pound
a hundredth or onehundredth
thirtynine millionths of an inch
twobillionths 
Do not use commas in any part of a fraction with fewer than five digits.
Connect numerator and denominator with a hyphen unless either already
contains a hyphen: onetenth one thirtysecond fortyfive hundredths twentyone thirtysixths
Note the difference: threehundred thousandths
(300/1000) and three hundredthousandths (3/100,000).
A fraction may be singular or plural depending on the intention of the writer. Generally the object of the preposition of following
the fraction governs the verb: Twothirds of Nepal's population lives
in these heavily farmed valleys; twothirds of them live here.
Use figures for all numbers that contain decimals: 3.4 inches of rain 22.25 inches of snow a 12.5billiondollar deficit
If the amount is
less than one, the unit of measurement is singular: .33 inch (not
inches) a day.
If the figure is a onedigit decimal, use a zero before
the point: 0.3 inch a day

