The Numerical System

In this section we will cover how numbers work in Vietnamese and what we can do with them

First, let's start off with some related vocab

Số - Number

Đếm - To count / To number

Đếm số - To count numbers

Example Sentence:

Vietnamese: Em của tôi đang đếm số với má.

English: My little sister is counting numbers with mom.

With that done, in Vietnamese, the basic numbers are as follows:

Numbers (Số)
1	2	3	4	5
một	hai	ba	bốn	năm
6	7	8	9	10
sáu	bảy	tám	chín	mười
100	1000	1,000,000	1,000,000,000	0
trăm	nghìn (North) / ngàn (South)	triệu	tỷ	không

When saying a number in Vietnamese, in general, the same rules apply as in English.

So for example:

721,346 = bảy trăm hai mươi một ngàn ba trăm bốn mươi sáu

bảy (seven) + trăm (hundred) + hai mươi (twenty) + mốt (one) + ngàn (thousand) + ba trăm (_three hundred) + bốn mươi (forty) + sáu (six)_

As seen above, the digits are still separated into threes and follow the same basic pattern that English follows except it doesn’t use the word . But, there also exists a few rules to be cautious of when saying a number in Vietnamese; relating mostly to pronunciation. Most of these changes are to make things easier to say again, but some are concepts not found in English.

Here is a list of the general rules when using numbers in Vietnamese:

Rule #1: You don’t need to connect numbers using the word “and” (và) between the hundreds and tens digit in Vietnamese.

Examples:

one hundred and twenty one = một trăm (one hundred) hai mươi mốt (twenty one)

eight hundred and thirty two thousand, six hundred and forty five =

tám trăm (eight hundred) ba mươi hai ngàn_ _(thirty two thousand) sáu trăm (six hundred) bốn mươi lăm (forty five)

Rule #2: The number 5 (năm) is pronounced lăm instead, when placed at the end of a number

Due to reasons relating to the history of the language, in Vietnamese, the word năm means both the English words “five” and “year”. So in order to differentiate these sounds, the word for 5 is modified so that there is no confusion between the 2 sounds. This only applies to the end of the word though.

Examples:

15 = mười lăm

55 = năm mươi lăm

Rule #3: The number 10 (mười) is pronounced mươi instead, when used for the numbers 20 through 99

This change is just for the sake of making things easier to say as the numbers become more complex.

Examples:

12 = mười hai

168 = một trăm sáu mươi tám

313 = ba trăm mười ba

Rule #4: The number 1 (một) is pronounced mốt instead, when used for the numbers 20 through 99 which include a 1, like 41

Like above, this change is just for the sake of making things easier to say as the numbers become more complex.

Examples:

1 = một

61 = sáu mươi mốt

125 = một trăm hai mươi lăm

Rule #5: The number 4 (bốn) is more commonly pronounced tư instead, when used for the numbers 20 through 99 which include a 4, like 34

The reasons for changing the pronunciation for this number is less about pronunciation, and is more about history this time. The word tư is a holdover from an entirely different set of names for the numbers that were used in older variants of Vietnamese that more closely follow Chinese pronunciations of these numbers. They don’t see nearly as much use nowadays, but they still sneak their way in occasionally. In this case, it is more common to use tư, but you can easily still use bốn and it will work. Just use what you’re most comfortable with

Examples:

4 = bốn

14 = mười bốn

44 = bốn mươi tư / bốn mươi bốn

774 = bảy trăm bảy mươi tư / bảy trăm bảy mươi bốn

Rule #6: When a number in the tens digit is a zero, it is represented in the word as linh (Northern) or lẻ (Southern)

This one is most likely going to be a new concept for most people reading this. In English, if we wanted to write the word 207, we would just say two hundred and seven. We already know to drop the and so that leaves the word two hundred seven. In order to fill the gap caused by the zero in the word we use the linh or lẻ. This helps make the word a bit less awkward to say

For Example:

207 = hai trăm linh bảy / hai trăm lẻ bảy

1,301 = một ngàn ba trăm linh một / một ngàn ba trăm lẻ một

Rule #7: When a number in the hundreds digit is a zero, it is represented in the word as không trăm, but only when there is a tens digit

The concept can be applied just like above except it applies for when the hundreds digit is missing like in the number 1051, but not when there isn’t a digit in the tens place like 1001.

For Example:

1,051 = một ngàn không trăm năm mươi mốt

1,001 = một ngàn linh một / một ngàn lẻ một