Use numerals with a diagonal line for fractional quantities such as "11/16 inch" or "5/8 acre." Also use this format to report any precise unit of measurement, such as "2/3-cup measure."
Write out common fractions that do not denote a quantity; for example, "one half of the page" or "a decrease of three fifths." Do not hyphenate the fraction except when it is a compound adjective, as in "two-thirds majority."
Include a zero before the decimal point for a decimal fraction less than one, such as 0.56. Omit the zero if you report a statistic that cannot be greater than one, such as a proportion or statistical significance; for example, use "p = .04" instead of "p = 0.04."