add up: meaning and explanation
You probably know that the basic meaning of the phrasal verb to add up is related to addition – e.g. Your meal cost $19 and mine cost $15. That adds up to $34. So why is the bill $50?
A more advanced way of using this phrasal verb is to say that a story or a claim is reasonable or believable, or that it makes sense. This is usually used negatively to say that we don’t believe what someone is telling us, because there is something wrong with the story. e.g. His story doesn’t add up. He says that he was at home all evening, but my friend says she saw him in the pub with his friends at 1am.
If you think that something is suspicious, you can say: Something about this doesn’t add up.
Have a go at these micro-dictation exercises to hear this expression being used in context – how much can you understand?
Accent: England (RP)
About the sentence
…I’ve got a feeling that he’s hiding something…
If you think that someone is hiding something, then you think that they are not being honest, open or truthful about something. They haven’t told you everything. e.g. Jess swears she doesn’t know anything about the break-in, but I think she’s hiding something.