Module 5

Numbers: Words or Numerals?

"Nine" or "9"? "Ten" or "10"? APA has one base rule, a set of exceptions that override it, and one place a numeral can never go. Learn those three layers and every number in your paper sorts itself out.

Layer 1 — The Base Rule: Words Below 10, Numerals for 10 and Up

Words: zero through nine The children completed three tasks across two sessions.

Numerals: 10 and above The survey included 25 items and took 15 minutes.

Ordinals follow the same pattern: the third grade, the fifth trial — but the 12th grade, the 21st trial.

Layer 2 — Exceptions: Always Numerals

Some numbers take numerals even when they're below 10, because they're precise, measured quantities:

Category	Example
Units of measurement	a 5-mg dose · 3 cm · 2 hr 15 min
Ages	4-year-olds · children ages 3 to 5
Percentages	only 8% of participants
Times and dates	at 8:30 a.m. · on May 3
Statistics, math, ratios	a mean of 6.2 · a ratio of 3:1 · multiplied by 4
Money	a $5 gift card
Scores & points on a scale	scored 4 on a 7-point scale
Numbered series & parts	Table 2 · Figure 1 · Grade 6 · Chapter 4 · item 8

Note a change from APA 6: sample sizes are no longer an automatic exception. An ordinary count of participants below 10 follows the base rule — "nine families withdrew," not "9 families withdrew" — unless it appears with a unit, percentage, or statistic.

Layer 2b — Exceptions: Always Words

Two situations flip the other way — words even for 10 and above:

Common fractions:

Correct one fifth of the class · a two-thirds majority

Universally accepted word phrases:

Correct the Twelve Apostles · the Five Pillars of Islam

Layer 3 — Never Start a Sentence With a Numeral

A sentence (or title or heading) may not begin with a numeral — spell it out, or better, reword so the number moves inside:

Wrong 48 participants completed the follow-up survey.

Fix 1: spell it out Forty-eight participants completed the follow-up survey.

Fix 2 (often better): reword A total of 48 participants completed the follow-up survey.

Fix 2 is usually the stronger choice when the spelled-out number gets long ("One hundred thirty-two participants...") or when you want the numeral visible for skimming readers.

Watch Out: The Rules Combine

Real sentences mix the layers. Both of these are correct — check each number against its own rule:

Mixed, and all correct The three intervention groups met for 6 weeks; 75% of the 4-year-olds completed all nine activities.

"Three" and "nine" are ordinary counts below 10 (words). "6 weeks" is a unit of time, "75%" a percentage, and "4-year-olds" an age (numerals) — the exceptions override the base rule.

Practice

Question 1

Which sentence follows APA number style?

Question 2

A sentence needs to begin with the number 132. What's the best APA-style opening?

Question 3

Which sentence handles the age correctly?

Question 4

Which sentence gets every number right?

🔢 Numbers: Words or Numerals?