(you) do the math

Figure out or put together the information for yourself. Do the math—can't you see that he's just using you to get ahead in the company? What happened? They convinced you to give them a lump sum as an "investment," and now they've cleared out of town. You do the math. Let's see, revenue is down and costs are going through the roof. You do the math—how long until we start hearing about layoffs?

do the math

1. Literally, to do a bit of arithmetic calculation. Primarily heard in US. Well, let's just do the math to see if you have enough in your savings account to afford a new car. OK, I did the math, and everyone owes $22.50. No, I know I don't have enough money for a down payment on a house—I don't need to do the math on that one.

2. To figure out or put together information for oneself. Primarily heard in US. Do the math—can't you see that he's just using you to get ahead in the company? A: "Why are you so upset?" B: "Do the math! The guy I really like left the party with another girl." This woman does not love you, OK? Do the math, Brian!

you do the math

AMERICAN

People say you do the math to mean that the person they are talking to should calculate something because the answer will be interesting, important or surprising. In Canada, a country of more than 30 million people, a novel is considered to have sold respectably if three thousand copies leave the shelf. You do the math.