Originally Posted by DRfrank
i still do the old take off the zero, cut it in half then add it to the one with the the zero taken off trick when it's not calculated in.
bill is 45.15
divide by 10
4.52
divide by 2
2.26
add together
6.78
voila! 15%
or you can do what i do and round off the the next 10, then multiply it by two and stick in a decimal point.
8.47=10.00=20.00=2.00
that way its usually over 20%. if its like 21.50, i'll round to 25 though.