5 ms·
I approximate a 20% tip by rounding up the (post-tax) total to the next $5 increment and then dividing by 5, e.g. $123.45 bill -> $25 tip. Alternately, in citi
by cpeterso 8y ago
I approximate a 20% tip by rounding up the (post-tax) total to the next $5 increment and then dividing by 5, e.g. $123.45 bill -> $25 tip.
Alternately, in cities with ~8-10% sales tax, you can double the sales tax and round up.
- jimmaswell 8y agoWhy all this work? Just multiply by two and move the decimal to the left. 54 -> 108 -> 10.8. 37 -> 74 -> 7.4.
- cpeterso 8y agoEveryone's brain works differently. :) I find division towards smaller numbers easier than multiplication towards larger numbers.