Large numbers are numbers bigger than the basic counting range, especially from 100 onward. In English, you build them by combining hundreds, thousands, millions, and so on in a fixed order. This module teaches how to say, read, and write large numbers clearly, including key differences between American and British usage.

English groups digits into threes from the right when naming large numbers. Each group has a name such as thousand, million, or billion, and you say the highest group first, then move down. Understanding the groups helps you avoid skipping or repeating a scale word.

Word/Phrase	🇨🇳 中文 词/短语	Definition	🇨🇳 中文 定义	Example	🇨🇳 中文 示例
ones	🧩 个位	the last digit group, up to 9	🧩 最后一位数字组，最高到9	7 is seven	🧩 7 是七
tens	🧩 十位	the second digit place, 10 to 99	🧩 第二位数字，10 到 99	42 is forty-two	🧩 42 是四十二
hundreds	🧩 百位	the third digit place, 100 to 999	🧩 第三位数字，100 到 999	600 is six hundred	🧩 600 是六百
thousand	🧩 千	1,000 to 999,999	🧩 1,000 到 999,999	12,000 is twelve thousand	🧩 12,000 是一万二千
million	🧩 百万	1,000,000 to 999,999,999	🧩 1,000,000 到 999,999,999	3,000,000 is three million	🧩 3,000,000 是三百万
billion	🧩 十亿	1,000,000,000 to 999,999,999,999	🧩 1,000,000,000 到 999,999,999,999	5,000,000,000 is five billion	🧩 5,000,000,000 是五十亿

Scale words name each 3-digit group: thousand, million, billion, and beyond. You do not pluralize a scale word when a number comes directly before it. You typically omit the word one before hundred and thousand in neutral speech, but it can be included for emphasis or clarity.

Rule	🇨🇳 中文 规则	Example	🇨🇳 中文 示例
Say groups from largest to smallest scale word	📌 由大到小说出分组对应的数量级词	2,040,000 is two million forty thousand	📌 2,040,000 是二百万四十万
Do not add s to scale words after a number	📌 数字后不要在数量级词后面加 s	6 million, not 6 millions	📌 6 million，而不是 6 millions
Use a scale word only if that 3-digit group is not zero	📌 只有当该三位组非零时才使用数量级词	7,000,005 is seven million five	📌 7,000,005 是七百万零五
One hundred is common; a hundred is also natural	📌 百一百常用；说成 hundred 也自然	100 is one hundred or a hundred	📌 100 是 one hundred 或 a hundred

For 100–999, English uses the pattern number plus hundred, then the rest of the number. In American English, it is common to say the remaining part directly after hundred without and. In British English, and is commonly used before the tens and ones part.

Rule	🇨🇳 中文 规则	Example	🇨🇳 中文 示例
Pattern: digit + hundred + remaining number	📌 模式：数字 + hundred + 剩余部分	342 is three hundred forty-two	📌 342 是 three hundred forty-two
US: and is usually omitted	📌 美国英语：通常省略 and	115 is one hundred fifteen	📌 115 是 one hundred fifteen
UK: and is often included before the last part	📌 英国英语：and 常在最后部分前出现	115 is one hundred and fifteen	📌 115 是 one hundred and fifteen
If there is nothing after hundred, stop there	📌 如果 hundred 之后无剩余部分，则仅说到 hundred	900 is nine hundred	📌 900 是 nine hundred

For 1,000–999,999, say the thousands group, then thousand, then the remaining part. If the remaining part is under 100, some speakers include and in British English, but it is optional in American English. When the last group begins with zeros, you still say the non-zero part normally.

Rule	🇨🇳 中文 规则	Example	🇨🇳 中文 示例
Pattern: thousands group + thousand + remainder	📌 模式：千位组 + 千 + 余数	58,210 is fifty-eight thousand two hundred ten	📌 58,210 是五十八千二百十
If the remainder is 0, end after thousand	📌 如果余数为 0 时，在 thousand 处结束	12,000 is twelve thousand	📌 12,000 是十二千
If the remainder is under 100, UK often uses and	📌 余数低于 100 时，英国常用 and	3,045 is three thousand and forty-five	📌 3,045 是三千和四十五
Do not say each zero; skip empty places	📌 不要逐零读出每个零；跳过空位	20,006 is twenty thousand six	📌 20,006 是二十万六

For one million and higher, the same 3-digit grouping rule applies: say the million group, then million, then the next group, continuing down. Each group can be spoken as a normal number from 1 to 999. This repetition makes very large numbers predictable once you know the scale words.

Rule	🇨🇳 中文 规则	Example	🇨🇳 中文 示例
Say each non-zero 3-digit group with its scale word	📌 将每个非零三位数分组连同其数量级词一起读出	4,501,020 is four million five hundred one thousand twenty	📌 4,501,020 是四百万五十万一千二十
Keep the order: million before thousand before hundred	📌 保持顺序：百万在前，千在前，百在前	9,010,300 is nine million ten thousand three hundred	📌 9,010,300 是九百万一万三百
If a middle group is 000, skip that scale word	📌 若中间组为 000，跳过该数量级词	7,000,400 is seven million four hundred	📌 7,000,400 是七百万四百

In modern English, billion usually means one thousand million, which is 1,000,000,000. Historically, some British usage used billion for a million million, but this is rare today and can cause confusion in older texts. In international contexts, it is safest to confirm whether the short scale meaning is intended.

Region	🇨🇳 中文 地区	Word	🇨🇳 中文 单词	Regional Definition	🇨🇳 中文 区域定义
US and modern UK	🌍 美英现代用法	billion	🌍 十亿	1,000,000,000	🌍 1,000,000,000
older UK texts	🌍 旧版英国文本	billion	🌍 十亿	1,000,000,000,000	🌍 1,000,000,000,000

In standard American writing, commas separate 3-digit groups in large numbers. Many other places use spaces or periods instead of commas, so formatting can vary internationally. When reading aloud, you do not say comma; you use scale words like thousand and million to reflect the grouping.

Region	🇨🇳 中文 地区	Word	🇨🇳 中文 单词	Regional Definition	🇨🇳 中文 区域定义
US writing	🗺️ 美国写作	comma grouping	🗺️ 逗号分组	1,234,567	🗺️ 1,234,567
many EU formats	🗺️ 许多欧盟格式	space grouping	🗺️ 使用空格分组	1 234 567	🗺️ 1 234 567
some EU formats	🗺️ 一些欧盟格式	period grouping	🗺️ 使用句点分组	1.234.567	🗺️ 1.234.567

For decimals, English says point and then reads digits after the point one by one, even in large numbers. The whole number part is read using the normal large-number rules. In some regions, a comma is used as the decimal marker in writing, but spoken English still typically uses point.

Rule	🇨🇳 中文 规则	Example	🇨🇳 中文 示例
Say point for the decimal marker	🔹 表示小数点的标记为 point	2.5 is two point five	🔹 2.5 是二点五
Read digits after point individually	🔹 小数点后面的数字逐位朗读	3.141 is three point one four one	🔹 3.141 是三点一四一
Read the whole number part normally first	🔹 先按通常读出整数部分	12,000.08 is twelve thousand point zero eight	🔹 12,000.08 是十二万点零八

English often uses approximate words to simplify very large numbers in speech and writing. You can round to the nearest thousand, million, or billion and signal it with about, around, or roughly. You can also use expressions like a couple of and a few to keep the meaning informal and approximate.

Word/Phrase	🇨🇳 中文 词/短语	Definition	🇨🇳 中文 定义	Example	🇨🇳 中文 示例
about	🧾 about	approximate, not exact	🧾 近似、非精确	about two million	🧾 大约两百万
around	🧾 around	approximate, conversational	🧾 近似、口语化	around 50,000	🧾 大约五万
roughly	🧾 roughly	approximate, slightly formal	🧾 近似、略正式	roughly 1.2 billion	🧾 大约 12 亿
a couple of	🧾 a couple of	approximately two	🧾 约等于两个	a couple of thousand	🧾 约两千
a few	🧾 a few	a small number, not exact	🧾 少量，非精确	a few million	🧾 几百万

To communicate large numbers clearly, pause at scale words and keep a consistent grouping rhythm. If a number is important, repeat it using digits or by restating the groups. When listening, focus on the scale words first, because they define the size of the number.