Why do we only say “an” before the number 8 but for any other number, we say “a”. For example, “an 18-year-old”, “a 17-year-old”, “a 91-year-old”
Because eight/eighteen/eighty-eight begin with a vowel-sound, and therefore get an 'an'. While seventeen, ninety-one or five do not and therefore get an 'a'.
The Short Answer
Because eight/eighteen/eighty-eight begin with a vowel-sound, and therefore get an 'an'. While seventeen, ninety-one or five do not and therefore get an 'a'.
Analysis
Key Concepts: Therefore, eight, eighteen
This explanation focuses on therefore, eight, eighteen and spans 25 words across 2 sentences. At 64% below the average Human Body explanation (69 words), the answer takes a direct, no-frills approach — sometimes the simplest explanation is the most effective.
What This Answer Covers
This is a focused, single-point answer that gets directly to the core of the question without detours.
How This Compares in Human Body
Ranked #442 of 500 Human Body questions by answer depth (top 89%). This is a brief primer — the answer is intentionally short. For questions with a single core mechanism, brevity can actually be a strength.
Frequently Asked Questions
Is there a simple explanation for why we only say "an" before the number 8 but for any other number, we say "a". for example, "an 18-year-old", "a 17-year-old", "a 91-year-old"?
Because eight/eighteen/eighty-eight begin with a vowel-sound, and therefore get an 'an'. While seventeen, ninety-one or five do not and therefore get an 'a'.
How detailed is this explanation compared to similar Human Body questions?
This is a brief answer at 25 words, ranked #442 of 500 Human Body questions by depth. The key concepts covered are therefore, eight, eighteen.
What approach does this answer take to explain we only say "an" before the number 8 but for any other numbe?
The explanation uses root cause analysis across 25 words. It is categorized under Human Body and addresses the question through 1 analytical lens.