In general spell out numbers one through nine. Use numerals for numbers 10 and above.
Spell out ordinal numbers fewer than 10th: first, third, ninth. Use numerals with th, st, nd, and rd, for numbers 10 and greater: 10th, 31st, 93rd. Do not use superscript text.
Avoid beginning sentences with numbers. When unavoidable, spell out all numbers that start a sentence, except when a year or numeral and letter combinations begin the sentence: 2010 was a great year. 3D movies are fun to watch.
Use numerals to indicate age.
Use numerals for dimensions, but spell out the unit of measure: 6 feet, 3 inches
Use numerals to indicate speed.
Use numerals when writing percentages or millions of dollars.
Percentages should be represented with numerals and a % symbol with no space between the number and symbol.
In ranges of numbers, numerals are separated by a hyphen with no spaces: The campus received 2-3 inches of rain.
In a range of years, the first year should be represented with all four digits; the second year needs only the last two digits. The years should be separated by a hyphen: the 2022-23 academic year