1. 左右 (zuǒyòu)
左右 literally means“left right", which is a fun way to express“around about". Add this word after your response to emphasize it's an approximation.
· 她 十歲 左右. (Ta shísuì zuǒyòu.) She's 10 years old, give or take.
· 那個箱子很重，八十公斤左右. (Nà ge xiāngzi hěn zhòng, bāshí gōngjīn zuǒyòu.) That box is very heavy, about 80kg.
2. 大概 (dàgài)
大概 includes the character 概(gài), which means“general" or“approximate". It's mostly interchangeable with 左右 and means "around about”and also“probably". Note that you use it before the object of your approximation.
· 她大概已經晚了三十分鐘。 (Tā dàgài yǐjīng wǎnle sānshí fēnzhōng.) She's already about half an hour late.
(Zhè dàgài shì jiàn hǎoshì.)
This is probably a good thing.
3. 應該 (yīnggāi)
This is a great word for when you're really not ready to commit to a yes, no or exact response! 應該 means "ought to be”or“should be about". Warning: In my experience, if you hear this word used as reassurance, such as “It’s probably going to be OK”, it might actually be a hint that all is NOT fine…
· 問題不大, 應該就快好了。 (Wèntí bù dà. Yīnggāi jiù kuài hǎole.) It's not a big problem. It ought to be fixed shortly.
· 應該可以. (Yīnggāi kěyǐ.) You should be able to do that. / It’s probably OK。
· 他應該快到了. (Tā yīnggāi kuài dào le.) He'll probably arrive soon.
4. 前後 (qiánhòu)
This is a word that indicates that the time given is“around about”or during a period of time. For example:
· 我明天給你打電話，中午前後吧。 (Wo mingtian geinidadianhua, zhongwu qiánhòu ba.) I'll call you tomorrow, around noon.
· 我們預計新店會在六月前後開業。 (Wǒmen yùjì xīndiàn huì zài liùyuè qiánhòu kāiyè.) We anticipate the new shop will open around June.