3 ms·
When tipping, I realized it's harder for me to multiply the bill (say $58) times 15% rather than times 30% / 2. In the latter case I simply do 60 * .3 / 2 which
by alexpetralia 6y ago
When tipping, I realized it's harder for me to multiply the bill (say $58) times 15% rather than times 30% / 2. In the latter case I simply do 60 * .3 / 2 which is $9. I thought about this after realizing, for example, that 18 * 5 is really 18 * 10 / 2.
Edit: just realized this is more about mental math than about back-of-the-envelope estimations
- bcrosby95 6y agoI usually just do something with 10s. I usually tip 20% so i knock off a zero then double it. If I tipped 15%, I would probably knock off a zero, then add half to it.