'putting two and two together' That one seems confusing. I can see putting one and one together to make two. Or to connect the dots between two things. Putting two and two together means you're making a thing out of 4 other things. .
American like the idioms 'here you are', 'there you go', 'there you are', and 'here you go'. People outside the U.S. sometimes ask, what does that stuff mean? .
I say lots of stupid sayings all the time.... I frequently say 'in my neck of the woods' as well as 'it's going to be curtains for you" and "That really burns my biscuit" I have no idea where they come from, but I live in the sticks and everyone is full of things like that.
See a man about a dog What we were always told as kids when we wanted to know where the growns-ups were going... To see a man about a dog...
"easier than shooting fish in a barrel" if you already have the fish in a barrel why do you need to shoot them?