Write numerals to express grades represented in scores and points on a scale. Numerals are numbers that are not spelled out; for example, the numbers 1, 21 and 100 are numerals. Also, use numerals for numbers 10 and above.
Write both words and numerals if there are two numbers in a series. For example, you can write "five 6-point scales" and "four 80-point exams." For large approximate amounts, use both numerals and written numbers, such as "5 million points."
Use the percent symbol with figures only. Spell out percent with written numbers. Examples of this are "five percent" and "5%." Place a leading zero before decimal fractions smaller than 1, for example, in "0.25 points."
Interpret ordinals below 10 as first, second, third, ninth and so on. For ordinals 10 and above, use numerals, such as 10th and 75th. For example, you can document one student as being in the top ninth percent of his class and another student as being in the bottom 30th.