Lesson 15 · いくつですか — every number, and what it does to what follows
Numbers, and the two ways of counting
Chapter 13 gave you the three big places and chapter 14 the clock. Neither gave you the numbers themselves. Today you get all of them — and the second, older set that Japanese kept beside them.
Japanese counting has a reputation for being hard. Almost none of that is the numbers, which are the most regular you will ever meet. It is the fact that there are two complete series, and that a number changes the shape of the word it lands on.
1.Two series, and one of them is already a counter
Japan borrowed Chinese numerals sometime around the fifth century and never threw away its own. Both survived, doing different jobs — 漢語数詞 the borrowed set, 和語数詞 the native one. Tap any cell to hear it.
The two series need JavaScript. Every word in them is on the cards in section 7.
Trick 1 · The native series does not need a counter, because it is one
いち cannot stand next to a noun. You cannot say two dog in Japanese any more than you can hand someone に and expect them to know what of. But ふたつ is complete on its own — point at apples, say ふたつ, and you have asked for two of them.
That つ on the end is the reason. It is a counter that was welded on so long ago it is no longer removable, which is why the series looks like ten words rather than ten numbers plus a suffix.
So the division of labour is clean:
| かんご いち に さん | わご ひとつ ふたつ | |
|---|---|---|
| Arithmetic, prices, years, phone numbers | ✓ all of it | — |
| Anything above ten | ✓ | — stops at とお |
| Counting things when you don't know the counter | — | ✓ |
| Joined to a counter — 〜えん 〜じ 〜かい | ✓ | only 〜にち and 〜り |
You have already used the native series without being told. Chapter 10's days of the month — ついたち, ふつか, みっか, よっか — are it, and so are ひとり and ふたり in section 5. It has been in the course since the calendar.
2.Every number, from four pieces
Above ten, Japanese has no irregular numbers at all. English has eleven, twelve and a -teen row that runs backwards; Arabic has أَحَدَ عَشَرَ and a whole band of frozen compounds. Japanese has multiplication and addition, in the order you say them.
25 — say what you see, left to right
2 × 10 + 5
に · じゅう · ご → にじゅうご
469 — the same operation, one place up
4 × 100 + 6 × 10 + 9
よんひゃくろくじゅうきゅう
Trick 2 · 一 is silent below 万 and compulsory above it
100 is ひゃく. 1,000 is せん. Neither takes an いち — saying いちひゃく is like saying one hundred and one hundred.
Then it flips: 10,000 is いちまん and 100,000,000 is いちおく, and the いち is not optional. Chapter 13 taught you why — 万 is a column, not a word for ten thousand, and a column has to be told how many of it there are.
The test that works: if English needs the word one, Japanese needs the 一. And Arabic sides with English — أَلْف stands alone too.
Type a number and hear it
This is the whole system running. Type anything up to nine digits and it will show you how the number is written, where the Japanese words actually break, and what it sounds like. Press 🎲 and it hides the answer until you have tried it yourself — that beat is where the learning is.
The number reader needs JavaScript. Section 2's four pieces and the sound changes in section 4 are everything it does.
3.Three numbers with two names, and a zero with three
Four, seven and nine each have two readings, and both are correct. Which one you use is a fact about the word that follows, not about the number — which is why it cannot be worked out and has to be met.
| Default | The other one | Where the other one is compulsory | |
|---|---|---|---|
| 4 | よん | し | しがつ Aprilよじ 4 o'clockよにん 4 people |
| 7 | なな | しち | しちがつ Julyしちじ 7 o'clockしちにん 7 people |
| 9 | きゅう | く | くがつ Septemberくじ 9 o'clock |
This is not a sound change, and filing it as one will cost you an hour
よじ is not よんじ worn down. It is a different word in the slot. Nothing phonetic is happening, so there is no rule to find, and a learner who goes looking for one will not stop looking.
The counter sheet marks these cells ✱ and puts them on a separate axis from the っ and ぷ cells for exactly this reason.
Why よん and なな won, when し and しち are the dictionary's own headwords: し is also 死, death, and く is also 苦, suffering. Buildings skip the fourth floor; hospitals skip the room. And しち has a plainer problem — down a bad telephone line it is very hard to tell from いち and はち.
Zero
| Word | Written | Used for |
|---|---|---|
| ゼロ | 〇 / 0 | the ordinary spoken one — a score, a count, a phone number |
| れい | 零 | the formal and written one — a temperature, a timetable |
| まる | 〇 | reading digits aloud, one at a time, as circle |
Trick 3 · You gave Japanese the word for zero
ゼロ is in katakana because it is the English word. English got it from Italian zefiro, and Italian got it from Arabic صِفْر — empty — along with the digits themselves. Cipher is the same word arriving by a different road.
So the one word on this page you can be certain of is the one that started in the language you already read, went round the world westward, and came back to you in a Japanese lesson wearing katakana.
4.The number tells you what happens next
Chapter 13 found two sound rules for 〜階 and the hundreds. Chapter 14 found the same two for 〜分 with the other mark. They were never two rules about two counters — they are one rule about the numbers, and now that you have all the numbers it can finally be stated.
Look at how the number ends. That is the whole of it.
Trick 4 · Learn the four that are safe, not the ones that change
2, 5, 7 and 9 never touch anything. That is exceptionless across all eight counters this course has taught, and it is four tenths of every table you will ever meet, gone.
It also works forward, on counters you have not been taught yet. A counter starting ほ or さ is going to fight with 1, 6, 8 and 10; one starting に, じ or a vowel will never fight with anything. You can predict 〜ほん before you meet it.
Two exceptions, and they are worth memorising as a pair
- ろくさい, not ろっさい. Six squashes before か and ぱ sounds but leaves さ alone. It is the only one of the four squashing numbers that ever declines.
- ろくせん, not ろっせん. The same refusal, one place up — which is why 6,000 is the regular cell in a column where 3,000 and 8,000 are not.
And which way a は-row counter goes after ん is fixed per counter, not predictable: ふん hardens to ぷん but ひゃく voices to びゃく. The rule tells you that something happens. The counter tells you which.
5.Nothing is counted bare
Japanese nouns do not change for number. ほん is book and books and always has been; there is no plural to reach for. So the language has to say how many somewhere else, and where it says it is on a word wedged between the number and the noun.
English — the noun carries it
three oranges
one letter, and the number can sit straight in front
العربية — the noun carries it, harder
ثَلَاثُ بُرْتُقَالَاتٍ
plural, genitive, and the numeral flips gender to disagree with it
日本語 — the noun carries nothing at all
みかんを みっつ
the noun is untouched; みっつ does the whole job
The two general counters
| Counter | 1 | 2 | 3 | How many? |
|---|---|---|---|---|
| 〜つ things | ひとつ | ふたつ | みっつ | いくつ |
| 〜にん people | ひとり | ふたり | さんにん | なんにん |
Trick 5 · いくつ has been the answer since chapter 6
You learned いくつ two months ago as a word meaning how many. It is いく 幾 — how many — plus this chapter's つ. You have been carrying the general counter around inside a question word all along.
The same trick reads なんにん: chapter 6's なん plus today's にん. That is the third question chapter 6 asked before the course could answer it, after いくら in chapter 13 and なんじ in chapter 14.
Two things about 〜にん repay noticing. First, its irregular cells are all vocabulary rather than sound — に is a nasal, so nothing can squash or harden against it, and the sheet's rule predicted that before the readings were written down. Second, the two survivors of the native series are sitting at the bottom of it:
ひとり · ふたり · さんにん · よにん · ごにん
One and two are native words with an old counter り that survives nowhere else in the modern language. From three it is にん and never anything else — except that 4 keeps よ and 7 keeps しち, which is section 3 turning up again.
Putting one in a sentence
Chapter 13 gave you ［〜を］ください. The quantity goes in it, bare, immediately before the verb:
| Japanese | Reads as | English |
|---|---|---|
| みかんを みっつ ください。 | tangerine-を / three-things / please give | Three tangerines, please. |
| みずを ふたつ ください。 | water-を / two-things / please give | Two waters, please. |
| なんにんですか。 | how-many-people / is it? | How many people? |
The quantity takes no particle, and that is all this course teaches about where it goes
みっつ sits there with nothing attached — no を, no の, nothing. Learn the slot, not a rule.
You can say みっつの みかんを ください and it is grammatical, but a Japanese speaker will not, and the difference is not small enough to ignore: putting the quantity in front implies you are distinguishing those three from some others. The plain order above is the one to have.
6.Arabic solves it by breaking the noun
This chapter is the one place where the Arabic is not riding along. Both languages have an elaborate machine for counting; they just built it on opposite sides of the phrase.
| How many | العربية | What happens to the noun |
|---|---|---|
| 1 | شَيْءٌ وَاحِدٌ | singular, and the numeral follows it like an adjective |
| 2 | شَيْئَانِ | the dual — no numeral at all, the noun says it |
| 3–10 | ثَلَاثَةُ أَشْيَاءَ | plural, genitive, and the numeral flips gender to disagree |
| 11–99 | أَحَدَ عَشَرَ شَيْئًا | back to singular, now accusative |
| 100+ | مِئَةُ شَيْءٍ | singular again, genitive |
Trick 6 · Each language deforms a different word
Japanese changes the counter's sound and never touches the noun. ろっぴゃく, いっぷん, さんがい — ひゃく, ふん and かい bend, and みかん is identical whether there is one or a thousand.
Arabic changes the noun and leaves the numeral comparatively alone. شَيْء becomes شَيْئَانِ, then أَشْيَاءَ, then شَيْئًا — number, case, all of it.
So the two languages are mirror images, and you already know one half of the mirror. When ろくさい refuses to squash, that is Japanese doing what ثَلَاثَةُ أَشْيَاءَ does: an agreement rule with an exception in it.
The reversed gender is the sharpest instance. شَيْء is masculine and takes ثَلَاثَة with the ة; دَقِيقَة is feminine and takes ثَلَاثُ without it — ثَلَاثُ دَقَائِقَ, which is on the counter sheet's 〜ふん row already. Japanese has no gender at all to disagree with, which is one fewer thing than the language you already have.
7.Thirty-two words
Eleven are the counting series, ten are the native one, and the rest are the places and the two general counters. Six already have a card elsewhere in the course — ひゃく せん まん from chapter 13, いくつ なんにん from chapter 6 and かず from chapter 5 — and they are here because a chapter about building numbers cannot be missing the pieces they are built from.
The word cards need JavaScript. Every word on them appears in the two series above or in the counters in section 5.
Drill them for meaning
The drill needs JavaScript. Every word it asks about is in the list above.
Why a dictionary is nearly useless on this page
Look these up in kana and watch what comes back. じゅう returns 銃, a gun, before it returns ten. きゅう returns 急, sudden, before nine. はち is also a bowl and a bee. なな hands you 七 read しち — the word pointing at its own other reading.
Numbers are the shortest words the language has, and a short string identifies almost nothing. Chapter 11 found this with かんこく, chapter 12 made it a trick with ご and そう; here it is true of an entire word class at once. It is the honest answer to why modern Japanese writes numbers as 1, 2, 3 — and why 一 二 三 exist at all.
8.Sources
- Minna no Nihongo I, 3A Corporation — 第11課 is where the object counters live: 〜まい, 〜ほん, 〜さつ, 〜だい, 〜ひき. Read that chapter's word list if you read one thing — with section 4 you can already predict which of them will fight with 1, 6, 8 and 10 before you are told.
- Japanese numerals, English Wikipedia — the two series, the readings of 0 to 10, the irregulars at 300, 600, 800, 3,000 and 8,000, and the rule that 千 immediately before a myriad word takes its 一 back: 10,000,000 is いっせんまん. It is also the source for し/死 and く/苦 in section 3.
- 助数詞, Japanese Wikipedia — that 〜つ covers 1 to 9 and stops, that only ひとり and ふたり keep the native reading, that 4 and 7 people are よにん and しちにん, and the generalisation section 4 rests on: voiceless counters geminate after 1, 6, 8, 10 and 100, and numbers ending in ん cause the change on the other side. It is also where the natural word order in section 5 comes from.
- Japanese counter words for why a counter is needed at all — Japanese has no singular/plural morphology, so the counting has to go somewhere else.
- Arabic grammar and the Arabic-language العدد والمعدود for section 6. The two agree exactly: 1 and 2 follow the noun as adjectives, 3–10 take a genitive plural with reversed gender, 11–99 a singular accusative, 100 and above a singular genitive.
- Jisho.org, over JMdict/EDICT (CC BY-SA 4.0) — every gloss and commonness tag, checked 2026-08-17. It is what found the homophones in the box above, and that 何人 has three common readings.
- Counters and their sound changes for section 4 in full, and lesson 13 for the four-digit grouping the number reader draws.