The five approximators and where each one sits

Mandarin has no single word for about. It has a small toolkit, and the trick is position, not vocabulary. Learn the slot each one occupies and the choice becomes mechanical.

• 左右 (zuǒ yòu) trails the number. Number + 左右 = around that number. Literally left-right, i.e. either side of.
• 大概 (dà gài) leads the clause or the number. 大概 + statement = probably / approximately.
• 差不多 (chà bu duō) sits in front of the quantity or comparison it nearly reaches. Literally lacking-not-much, i.e. almost.
• 几 (jǐ) replaces an unknown small number in the number slot itself. 几 + measure word = a few / several.
• 来 (lái) wedges inside the number, between the round figure and the measure word. 十来个 = ten or so.

So 左右 points back at the number behind it, 大概 points forward at everything after it, 差不多 leans on the quantity in front of it, 几 stands where a number would stand, and 来 buries itself inside the number. Everything below is detail.

左右: around a number, trailing

左右 is the workhorse for around / roughly a quantity. It comes immediately after the number-plus-measure phrase and softens it to either side. Nothing else moves.

• 三十左右 (sān shí zuǒ yòu) - around thirty
• 三十个人左右 (sān shí gè rén zuǒ yòu) - around thirty people
• 五点左右到 (wǔ diǎn zuǒ yòu dào) - arrives around five o'clock
• 一个小时左右 (yí gè xiǎo shí zuǒ yòu) - about an hour

The test: if the approximator follows the number, you want 左右. It works with counts, clock times, ages, money and durations alike, and it always trails. Because it attaches to a full measured quantity, the measure word stays put: 三十个人左右, not 三十左右个人. For how the number-measure-noun string is built in the first place, see classifiers; for clock times and dates specifically, see numbers, time and dates.

大概: probably / approximately, leading

大概 means probably or approximately and sits at the front of what it qualifies, before the number or before the whole clause. It is an adverb, so it lives in the adverb slot - after the subject, before the verb or the quantity.

• 他大概三十岁 (tā dà gài sān shí suì) - he is about thirty years old
• 大概有三十个人 (dà gài yǒu sān shí gè rén) - there are about thirty people
• 他大概不来了 (tā dà gài bù lái le) - he probably is not coming
• 我们大概八点出发 (wǒ men dà gài bā diǎn chū fā) - we will probably set off around eight

The test: if the approximator leads, you want 大概. Note the two senses living in one word. With a number it means approximately (大概三十 - about thirty); with a verb phrase it means probably (大概不来 - probably not coming). The same flavour of speaker-uncertainty also surfaces through modal verbs; see modals and intent. 大概 and 左右 happily co-occur for double hedging: 大概三十左右 (dà gài sān shí zuǒ yòu) - probably around thirty or so.

差不多: almost / about the same

差不多 literally means the difference is not much, and it covers two English ideas: almost (nearly reaching a quantity) and about the same (two things barely differ). It sits in front of the quantity or the thing being compared.

• 差不多三十个 (chà bu duō sān shí gè) - almost thirty (just short of thirty)
• 差不多到了 (chà bu duō dào le) - almost there / nearly arrived
• 他们俩差不多高 (tā men liǎ chà bu duō gāo) - the two of them are about the same height
• 这两个差不多一样 (zhè liǎng gè chà bu duō yí yàng) - these two are pretty much the same

The test: if the meaning is almost reaching or barely differing, you want 差不多. The comparison sense leans on the equality frame 一样 and on adjectives used as predicates; see comparatives for 一样 and 比, and adjectives as stative verbs for why 高 needs no is. Crucially 差不多 is one-sided: 三十左右 means either side of thirty (could be thirty-two), but 差不多三十 means just under thirty, not yet arrived.

几: an unspecified few / several

几 is not a softener you bolt on; it is a number you swap in. It takes the slot a real number would occupy, before a measure word, and means an unstated small quantity - a few, several, normally somewhere from two to nine.

• 几个人 (jǐ gè rén) - a few people / several people
• 几本书 (jǐ běn shū) - a few books
• 十几个 (shí jǐ gè) - a dozen or so (literally ten-several, i.e. eleven to nineteen)
• 几百块 (jǐ bǎi kuài) - a few hundred yuan

The test: if you mean an unknown small count and there is a measure word waiting, you want 几. It is the same character as the question word 几 (how many); see question words. Context, not form, tells the two apart: 几个人？ with rising intonation asks how many people, while 几个人来了 states a few people came. Stacked with round numbers it builds ranges: 十几 (teens), 几十 (tens, i.e. dozens), 几百 (a few hundred).

来: ten or so, infixed in the number

来 is the odd one out. It is an infix: it slots inside the number, between a round figure (ten, hundred, a unit of ten) and the measure word, to mean that round figure, give or take a bit. It only attaches to round numbers.

• 十来个 (shí lái gè) - ten or so / about ten
• 二十来岁 (èr shí lái suì) - twenty-odd years old / in their twenties
• 三十来个人 (sān shí lái gè rén) - thirty or so people
• 百来块 (bǎi lái kuài) - a hundred or so yuan

The test: if you want round-number-plus-a-bit and the number is round (ends in zero or is a clean hundred), you want 来 jammed in before the measure word. It cannot attach to a non-round number: 三十三来个 is impossible. 二十来岁 is the idiomatic way to say someone is twentysomething, and it leans slightly upward (twenty and a touch more), where 二十左右 sits evenly on both sides of twenty.

Minimal pairs side by side

The cleanest way to feel the system is to hold the number still at thirty and change only the approximator and its seat.

Same target figure, five different seats, five different shades of approximate. 左右 is symmetric, 差不多 undershoots, 来 nudges upward, 大概 just hedges, and 几 abandons the exact figure altogether.

The errors that catch everyone

Error 1: putting 左右 before the number

左右 trails. Learners who map it onto English around want to lead with it, as English does. It does not lead.

• ✗ 左右三十个人 - WRONG. 左右 cannot precede the number. Use 三十个人左右 (sān shí gè rén zuǒ yòu) - around thirty people, or lead with 大概: 大概三十个人 (dà gài sān shí gè rén).

Error 2: stacking 大概 and 左右 wrongly, or treating them as identical

Both hedge, but they are not interchangeable and they do not swap seats. 大概 leads, 左右 trails, and when both appear 大概 stays at the front.

• ✗ 三十大概 - WRONG. 大概 never trails. It is 大概三十 or, trailing, 三十左右.
• 大概三十左右 (dà gài sān shí zuǒ yòu) - CORRECT, with each marker in its own seat: probably around thirty.

Error 3: 差不多 where you meant 左右

差不多 undershoots; 左右 is even. Saying 差不多三十 when you mean about thirty, could be a bit over implies you have not quite reached thirty, which may be a factual error.

• 差不多三十 (chà bu duō sān shí) - almost thirty (twenty-eight, twenty-nine, not yet thirty).
• 三十左右 (sān shí zuǒ yòu) - around thirty (could be twenty-eight or thirty-two). Pick by which you mean.

Error 4: 来 on a non-round number, or forgetting the measure word

来 only infixes into round numbers and still needs its measure word behind it.

• ✗ 三十三来个 - WRONG. The number is not round. Use 三十三个左右 (sān shí sān gè zuǒ yòu) - about thirty-three.
• ✗ 十来人 - WRONG in standard usage for a counted noun; the measure word stays: 十来个人 (shí lái gè rén) - ten or so people.

Error 5: forgetting 几 carries a measure word

几 is a number, so it behaves like one: it needs a classifier before the noun, exactly as 三 would.

• ✗ 几人 - WRONG (outside fixed literary phrases). It is 几个人 (jǐ gè rén) - a few people, just as you would say 三个人. See classifiers.

What to drill

1. Fix each marker to its seat. 左右 trails, 大概 leads, 差不多 leans on the quantity, 几 replaces the number, 来 infixes inside a round number. Position decides everything.
2. Distinguish symmetric from one-sided. 左右 spreads either side; 差不多 undershoots; 来 nudges upward. Choose by which direction your estimate leans.
3. Keep the measure word. 几 and 来 both still demand a classifier - 几个人, 十来个人 - because the count is still being measured.
4. Stack 大概 and 左右 for soft estimates. 大概三十左右 is natural and idiomatic; just keep 大概 at the front and 左右 at the back.
5. Read the minimal pairs aloud. 三十左右 / 大概三十 / 差不多三十 / 三十来个 / 几十个 back to back trains the slot and the shade of meaning at the same time.

For building the number-measure-noun string these markers attach to, see classifiers and numbers, time and dates. For the comparison sense of 差不多, see comparatives. For 几 as a genuine question word, see question words.