Back-Of-The-Envelope Calculation
Categories: Accounting, Metrics, Banking
Quick: What would 1,000 Thousand Dollar bars cost at Costco at $1.15 a piece?
No, it's not 1,000 times 1,000. You're not good enough at math to do the multiplication in your head, so you grab whatever scrap of paper you have (say, an envelope) and do a quick "1,000 x 1.15 gives you 50 plus 100 plus 1,000, or $1,150."
With cell phones, back-of-the-envelope calculations are probably heading for extinction. It's just a quick calculation to give you enough information to get a deal underway.