The Chinese are famously pretty vague in giving answers. As most will readily admit, they prefer to offer estimations rather than specifics, especially if there may be consequences involved. Instead of getting frustrated, we straight-talking foreigners can benefit from adopting the "vague" approach ourselves.
In order to help give your own answers an authentic air of enigma, here are four ways to say "roughly speaking", "about" or "probably" in Mandarin:
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.
(Tā shí suì zuǒyòu.)
She's 10 years old, give or take.
(Nà ge xiāngzi hěn zhòng, bāshí gōngjīn zuǒyòu.)
That box is 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.
((Nà'er) lí zhè'er dàgài yǒu èrshí fēnzhōng chēchéng.)
It's probably a 20-minute drive from here (to there).
(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. 应该 (yīnggāi)
This is a great word for when you're really not ready to commit to a yes, no or exact response! 应该 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…
(Wèntí bù dà. Yīnggāi jiù kuài hǎole.)
It's not a big problem. It ought to be fixed shortly.
You should be able to do that / It's probably OK.
(Tā yīnggāi kuài dàole.)
He'll probably arrive soon.
4. 前后 (qiánhòu)
This is a word that indicates that the time given is "around about" or a during a period of time. For example:
(Bǎobao de yùchǎnqí shì sì yuè 9 hào qiánhòu.)
The baby is due around April 9th.
(Wǒmen yùjì xīndiàn huì zài liù yuè qiánhòu kāiyè.)
We anticipate the new shop will open around June.
So that's it, 左右! Please try out these phrases and see how they work for you. I hope it's of help as you navigate the sometimes confusing, always engaging, wonderful world of Mandarin.