If your boss asks you to give back some summary numbers (“how many applications do we support?” “how many projects are we going to have next year?” “how many people are working on new development projects?”), unless the numbers are a push-button away or embedded in your brain, don’t just tally things up on your fingers or on the back of some scrap paper and feed back the summary numbers.
Why? Because sure as shooting as soon as you do — or, better yet, a few weeks later — your boss is going to then ask you for the detail behind it all. And if you gave an answer out of your hat, or including some assumptions that aren’t written somewhere, you will never, ever, ever be able to give him the same numbers (“I thought you said it was seven applications, but you only listed six here”), and you will have to do the work you should have done the first time to come up with the accurate tally. And your boss will doubtless be asking for the detail in order to provide an answer to someone Right Now, and not be pleased with either discrepancies or delays.
I’ve been burned by this too many times, so now I endure the ribbing of my cohorts by building the underlying detail on spreadsheets, letting them calculate the tallies, then transferring them over to wherever my boss wants the info. The nice thing is that if the assumptions change (“can you break out work by VPs?” “can you only count permanent hires rather than contractors”) it’s not a matter of starting over from scratch. It takes more time up front, but boy is it nice to be the first to respond for the second request for info.
That said — keep the backup in your “back pocket” until asked for it. Don’t send it all to the boss, who really only wants the summary up front, not to wade through the extra detail.
Thus Endeth the Lesson.