The Numeric System

Numbers starting from 100

We already learned all the numbers up to 99 in the first chapter. We will now learn the numbers 100 up to 10 quadrillion. If you need a quick review, here are the first 10 numbers.

Numerals 1 2 3 4 5 6 7 8 9 10
Reading いち さん し/よん ろく しち/なな はち きゅう じゅう

Here are the additional units for numbers starting from 100.

Numerals 100 1,000 10,000 10^8 10^12
Kanji 一万 一億 一兆
Reading ひゃく せん いちまん いちおく いっちょう

Note: Units larger than 「千」 require another preceding number and cannot be used by themselves. For example, 「万」 does not mean 10,000, you need to add a one: 「一万」.

Because the Japanese numeral system is based on units of four not three, the same units get repeated once you get past 10,000 until you get to 100,000,000. In other words, numbers are organized as 1,0000, 1,0000,0000, 10^12, 10^16 and so on.

You’ll need to pay careful attention to reading changes for some sound combinations. The chart below outlines the numbers that are pronounced slightly differently.

Numerals Kanji Reading
300 三百 さんびゃく
600 六百 ろっぴゃく
800 八百 はっぴゃく
3000 三千 さんぜん
8000 八千 はっせん
10^12 一兆 いっちょう


Large numbers are rarely written in all Kanji as you can imagine something like 「二百三十万九千四百三十一」 would be difficult to read. You will usually see a combination of numbers and Kanji or just numerals altogether.

  1. 1,234 【せん・に・ひゃく・さん・じゅう・よん】 – 1,234
  2. 5万3千 【ご・まん・さん・ぜん】 – 53,000

Other numbers

Several ways to say zero and other types of numbers are listed below. 「まる」 meaning “circle” is similar to how we use “O” (the letter) in things like phone numbers, room numbers, and addresses.

  1. 零 【れい】 – zero
  2. ゼロ – zero
  3. まる – circle; zero
  4. ~号室 【~ごう・しつ】 – suffix for room numbers
  5. マイナスX – negative X
  6. 点 【てん】 – period; dot; decimal point
  7. X.Y 「X・てん・Y」 – X.Y
  8. X分のY – Y/X (Y of X parts)


  1. 203号室 【に・まる・さん・ごう・しつ】 – room 203
  2. 23.5 【に・じゅう・さん・てん・ご】 – twenty three point five
  3. 四分の一 【よん・ぶん・の・いち】 - fourth (1/4)
  4. マイナス5 – negative five

It’s so confusing!

John: Oh already! (I) don’t understand Japanese numbers at all!

アリス:確かに難しいよね。日本語では、四単位で数えるから、私は、四を足して、三で割って、英語の数字に変えるよ。例えば、百万は、二足す四で六だから、1 millionになる。
Alice: It’s certainly difficult, isn’t it? Because in Japanese (you) count by units of four, I just add four, divide by three, and change (it) into (the) English number. For example, ひゃくまん is 2 plus 4 and (it’s) six so it becomes 1 million.

John: No, (I) don’t understand at all! Lee-kun, it isn’t difficult?

Lee: Korean is the same as Japanese so (it’s) easy, you know.

John: That’s cheating!

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