Números Ordinais Em Inglês De 1 A 31

Como dominar os ordinais em inglês sem precisar decorar tudo de uma vez

Ordinal numbers in English follow a handful of patterns, but the exceptions are what trip people up. Once you understand the system, memorizing numbers 1 through 31 takes about ten minutes. After that, the pattern extends indefinitely. The main problem isn't the concept—it's that certain forms don't follow the obvious rule, and beginners write them wrong consistently. Here is the actual list. I'm including the abbreviation because that's what you'll see in practice, not just the full word. 1st – first
2nd – second
3rd – third
4th – fourth
5th – fifth
6th – sixth
7th – seventh
8th – eighth
9th – ninth
10th – tenth
11th – eleventh
12th – twelfth
13th – thirteenth
14th – fourteenth
15th – fifteenth
16th – sixteenth
17th – seventeenth
18th – eighteenth
19th – nineteenth
20th – twentieth
21st – twenty-first
22nd – twenty-second
23rd – twenty-third
24th – twenty-fourth
25th – twenty-fifth
26th – twenty-sixth
27th – twenty-seventh
28th – twenty-eighth
29th – twenty-ninth
30th – thirtieth
31st – thirty-first

The patterns are straightforward once you separate them into groups. For multiples of ten—twenty, thirty, forty, fifty—you drop the final "y" and add "ieth." That gives you twentieth, thirtieth, fortieth, fiftieth. The hyphenated compound numbers follow the same logic: you write the ten part as an ordinal and the unit part as an ordinal, connected by a hyphen. Twenty-first, not twenty-one-st. This is where most mistakes happen. People write "twentyone-st" or forget the hyphen entirely. Now the irregulars. These three don't follow any spelling pattern you can derive from the cardinal number. One becomes first. Two becomes second. Three becomes third. After that, five drops the "v" and adds "fth." Eight drops one "t" and adds "th"—so it's eighth, not eightth. Nine drops the "e" and adds "nth"—ninth, not nineth. Twelve changes "ve" to "f" and adds "th"—twelfth. Those are the only ones that diverge from the standard rule within the 1–31 range. I ran into a specific problem a few years ago when I was proofreading a legal document. The drafter had written "31st" as "31-st" with a hyphen between the numeral and the suffix. That's wrong. The correct abbreviation format is numerals directly followed by the suffix letters with no space and no hyphen: 31st, 21st, 2nd, 3rd. Only the full spelled-out form uses a hyphen, and only when it's a compound ordinal like "twenty-first." I spent about forty minutes going through twelve pages fixing these. It sounds trivial but it matters in formal writing because consistency signals competence.

Here's something most beginners miss: the pronunciation of "twelfth" and "eighth" causes more errors than anything else. "Twelfth" is pronounced /twlf/ — the "v" sound stays. People hear "twelth" without the v and write it wrong. "Eighth" has a silent final "t" sound merged with the "th" — it's /et/, not "eight-th." If you're teaching someone or preparing study materials, record yourself saying these aloud and compare them to a native speaker. Listening is more useful than memorizing the spelling for these two. Another nuance that isn't widely explained: ordinal numbers in English are primarily adjectival. You say "the fifth chapter," not "the five chapter." When they function as nouns, you drop the article and pluralize — "the fifths" in math class, or "thirds" when dividing something. But in everyday usage, nearly every ordinal you encounter will sit before a noun. Dates are the one exception where they stand alone: "March fifth" or "the fifth of March." Both are correct. The first is more American. The second is more British and also more common in formal contexts. The limitation I want to be honest about: this system works beautifully for 1 through 31 and extends cleanly to much larger numbers, but it becomes unreliable when you hit very high ordinals in spoken English. Beyond, say, the hundredth, even fluent speakers start mixing up "-teenth" and "-tieth" endings, especially under pressure. If you need precision with large ordinals — say, numbering documents or chapters past 100 — always write them out and double-check. Don't trust your ear alone. It's faster to look it up than to publish something wrong.

A practical tip that actually works: don't study these in isolation. Put them in context immediately. Write out the dates of your last thirty birthdays in English. Number thirty items around your house. The brain retains patterns embedded in meaning far better than abstract lists. I've watched people spend hours memorizing the list and still confuse "fifth" and "fiveith" two days later. Context solves that. One more thing about abbreviation style. In American English, you'll commonly see the suffix attached directly: 1st, 2nd, 3rd, 4th. In British English, you may occasionally see a superscript format in printed material: 1, 2, 3. Both are correct. The superscript version is mostly found in formal typography and legal documents. For digital communication, the inline version is standard everywhere. Don't overthink it — just be consistent within a single document.