Why do I need to know exact?
You will hear this a lot in slightly more slangy conversations and it will come in handy if you want to let someone know that you're on the same page
What does it mean?
Exact is a shortened version of exactement – exactly.
You can use it two ways, one in its more literal sense of exactly
Je vais prendre ma pizza exactement la même mais sans anchois, s'il vous plaît – I'll have my pizza exactly the same, but without anchovies, please.
Or you can use it in its more colloquial sense as a way of emphatically agreeing with someone.
In this sense it translates more like 'you're so right' 'I couldn't agree more' or 'we're on the same page'
So if you've heard something that you strong agree with, you could say
Oui, exact! C'est entièrement la faute du patriarcat! – You're so right! It is all the fault of the patriarchy!
Alors tu penses que l'oie est meilleure que la dinde à Noël? Exact! – So you reckon that goose is better than turkey at Christmas? Too right!
You will also frequently hear C'est exactement ça! – That's just it!
And if you find yourself doing a lot of emphatic agreement (unlikely as it sounds over the festive period) you could use carrément or franchment in roughly the same way.