Cardinal Numbers from Zero to Ten

Vietnamese cardinal numbers from zero to ten are short and regular, but natural counting involves more than replacing English number words. A number often comes before a classifier and noun, dates run from smaller to larger calendar units, and some digits later acquire positional forms such as mốt, tư, and lăm. This page establishes the basic forms không through mười and shows how they enter everyday phrases. Building tens and hundreds belongs on Tens, Hundreds, and Positional Lẻ.

The basic forms

Every written form carries its tone: bốn, năm, sáu, bảy, tám, chín, and mười are not optional spellings with decorative marks. Tone and vowel quality identify the word.

Numbers, classifiers, and nouns

With a countable noun that requires a classifier, the basic order is number + classifier + noun:

English says “two books” with a plural ending. Vietnamese normally leaves the noun unchanged and lets the numeral plus classifier express countability. The classifier is not equivalent to English plural -s; it categorizes the counted referent.

Some common nouns count directly because they are measure words, time units, currency units, or human-role nouns: hai ngày “two days,” ba tháng “three months,” năm đồng “five đồng,” mười học sinh “ten students.” Do not insert cái everywhere.

Zero: digit, quantity, and absence

Không names the digit zero, but the same form also participates in negation. Context distinguishes “zero” from “not/no.”

When reporting a score, temperature, or exact quantity, không behaves as a numeral. With không có, it denies existence or possession. English speakers should not assume that every English no corresponds to a bare numeral.

One through ten in everyday time and quantity

Cardinals remain unchanged after ordinary time units. Vietnamese commonly says tám giờ “eight o'clock,” năm phút “five minutes,” and ba ngày “three days.” At the half hour, rưỡi follows the unit:

Age uses number + tuổi, without the English verb to be before an adjective-like age phrase:

Small prices place the currency unit after the number. In real modern transactions, prices usually exceed ten đồng, but the grammatical order is already visible in năm đồng. The dedicated money page covers larger prices, colloquial shortening, and currency context.

In a decimal, phẩy introduces the decimal part, and short decimal parts are commonly read digit by digit: hai phẩy năm is 2.5, while không phẩy năm is 0.5. This is a different construction from rưỡi in clock time: tám giờ rưỡi means half past eight, not “8.5 o'clock.”

Dates and ordinals are related, but not identical

Vietnamese dates normally proceed day + month + year, with the unit words stated before their values: ngày 7 tháng 10 means “October 7” in American English and “7 October” in British English.

Do not reorder the spoken phrase because an American form displays the month first. The digit 7 is read bảy, so the full spoken date is ngày bảy tháng mười.

Thứ + number forms many ordinals and weekday names. Thứ hai can mean “second” in a sequence, while in calendar context it is Monday. This page only introduces the contrast; Ordinals with Thứ explains thứ nhất, weekday conventions, and context in detail.

A preview of positional variants

The basic digits do not always keep the same form inside larger numbers. After tens, một may appear as mốt, bốn may appear as tư, and năm appears as lăm in the relevant positions.

These are not separate digits and not optional tone changes. They are conditioned numeral forms. The full rules and acceptable alternatives belong on Mốt, Tư, and Lăm after Tens.

Minimal contrast: what each construction signals

The number word does not carry the whole interpretation. Thứ, ngày, tháng, giờ, and rưỡi tell the listener what kind of numerical information is being given.

A natural scheduling dialogue

Changing tám giờ to tám giờ rưỡi changes the appointment by thirty minutes; changing ngày 7 to ngày 8 changes the day. Classifier tấm makes ba tấm vé a counted ticket phrase, while ba người counts people directly in this context.

Common Mistakes

1. Omitting a required classifier

The classifier quyển categorizes bound books. Headlines and commercial labels may compress some numeral phrases, but English-style number + bare noun is not a safe general pattern.

2. Adding a classifier to every noun

Human-role nouns such as học sinh can follow the numeral directly; người is possible in different constructions, but cái is not.

3. Using the basic digit form in a later positional environment

The repair uses lăm, the expected form of five in fifteen.

4. Copying American date order

Vietnamese names the day before the month in the standard full date frame.

5. Translating “half past eight” word for word

Vietnamese states the hour, the unit giờ, and then rưỡi “and a half.”

Key Takeaways

• Learn the toned sequence from không to mười as complete Vietnamese forms.
• The default count phrase is number + classifier + noun, but time units, measures, currencies, and many role nouns count directly.
• Context words such as thứ, ngày, tháng, giờ, and tuổi determine how a cardinal is interpreted.
• Vietnamese dates put the day before the month, and tám giờ rưỡi expresses 8:30.
• Mốt, tư, and lăm are positional variants in larger numbers, not replacements for the basic digits everywhere.