For anyone who doesn't know the whole trick: 2^10 ~= 1_000 (2.5% error) 2^20 ~= 1_000_000 (4% error) 2^30 ~= 1_000_000_000 (7% error) Because of e

For anyone who doesn't know the whole trick: 2^10 ~= 1_000 (2.5% error) 2^20 ~= 1_000_000 (4% error) 2^30 ~= 1_000_000_000 (7% error) Because of exponentials, each power of 5 between is about 1/30 of the way to the next power of 10 (2^5 = 32, 2^15=32_768, etc). With this framework you have good anchors for all 2^(5k), which means you only ever have to divide/multiply by at most 8 to get a good approximation for any power of two. Now you can impress your coworkers with your amazing ability to fudge powers of two in your head.