HSKReadyGet the appHSK 4 · Special expressions › Number expressions
Approximate Numbers with 大约, 左右, and 前后
Chinese uses 大约, 左右, and 前后 to give estimates when an exact number is unavailable or unnecessary. Learn their typical positions and how to choose among them.
这台电脑大约八千块。
大约 comes before the estimated price.
Read the full explanation and examples
Why Use Approximate Numbers?
The outline identifies this point as HSK Level 4 number expression: using 大约, 左右, and 前后 to express approximation. These forms are useful when giving an estimate rather than a precise count, price, distance, duration, age, or time. The estimate may be based on memory, changing conditions, or a practical need for only a rough figure.
大约: Put the Estimate First
大约 means “about” or “approximately.” It normally comes before the number or quantity it qualifies. It works in many everyday estimates, including prices and counts. A classifier or unit may follow the number, depending on the noun and measurement.
这台电脑大约八千块。
大约 comes before the estimated price.
左右: Add “About” After the Quantity
左右 follows the quantity it estimates: 五公里左右 or 两个小时左右. When the approximate quantity modifies a following noun, use an appropriate 的 phrase: 二十个左右的学生 or 两个小时左右的会. Do not use number + classifier + 左右 + noun as a general template without 的. Keep the intended quantity clear.
车站离这里五公里左右。
左右 follows the distance phrase.
我们开了两个小时左右的会。
左右 follows the duration phrase; the whole phrase describes the meeting.
前后: Around a Time or Age Point
前后 literally suggests “before and after.” After a time expression or age, it means approximately around that point, allowing some variation on either side. The width of the range is not fixed: it depends on the context and how precisely the speaker needs to communicate. It is especially useful for events occurring around a time or life stage.
他三十岁前后开始学中文。
前后 places the beginning around that age, not necessarily exactly on his thirtieth birthday.
他们下午三点前后出发。
前后 alone marks an approximate departure time. 大约下午三点前后 can also occur for a deliberately loose estimate, but two markers are not needed for this basic example.
Choose by Meaning and Placement
- Use 大约 before the estimate when you want to frame a number as approximate: 大约 + number or quantity.
- Use 左右 after a number phrase when you want to mark that quantity as approximate: number phrase + 左右.
- Use 前后 after a time or age point when the meaning is “around that point,” with variation on either side.
- The forms can overlap in broad meaning, but they do not always sound equally natural in the same sentence. When both choices are possible, sentence focus and context guide the choice.
- Avoid piling up several approximation words just to signal uncertainty. One clear marker is generally enough unless the context deliberately emphasizes an especially rough estimate.
Frequently asked questions
Can I replace 大约 with 左右 in every sentence?
Not mechanically. Both can express an estimate, but their usual placement differs: 大约 comes before the number, while 左右 follows the number phrase. Choose the construction that fits the sentence and intended emphasis.
How many minutes or years does 前后 include?
There is no fixed interval supplied by this expression alone. The context, the event, and the level of precision needed determine how wide “around” is.
