America and its Customs

Anthrocon website wrote:Let us examine your journey from door to door and illustrate where a gratuity is expected. Before we begin, however, it is useful to note that the number 15 (as in 15%) will appear frequently in this dissertation. For those who are mathematically challenged, it is simpler perhaps to divide the total by 10, and then in half, and add those two values together. For example, for a $23.00 bill, divide the total by ten (that is, move the decimal point one hop to the left) which gives $2.30. Then divide that in half ($1.15, which I hope should be easy enough for the reader to derive on his own). Now add the two together: $2.30 plus $1.15 is $3.45. It is acceptable to offer exact change, but rounding the total to the next-highest quarter (or preferably the next-highest dollar) makes the traveler appear less of a cheapass; thus, you could quite properly count out $26.45, but to hand the server $27 with "keep the change" will.