Move the decimal place one to the left of the subtotal. (Don’t tip on taxes lol.) Say, $59 becomes $5.90. Then multiply by two. So tip roughly $12. Even if you mess up and round down when you shouldn’t, at worst you’d only tip $1.80 less than you “should”.
Move the decimal place one to the left of the subtotal. (Don’t tip on taxes lol.) Say, $59 becomes $5.90. Then multiply by two. So tip roughly $12. Even if you mess up and round down when you shouldn’t, at worst you’d only tip $1.80 less than you “should”.