I have a perpetual calendar that only has five rows. Therefore, in some
months, such as this one (July 2005), I run out of room for the "31"
tile. I want to make my own tiles that allow one day to include split
dates, e.g., 24/31 for this month, which would go in the Sunday slot
at the beginning of the bottom row. Here's my question: Is there a way
to figure out how many of those types of tiles I will need, and which
number combinations, to make the
calendar ready for any month forever?

Hi, k8hayes-ga:

If the days of the week are fixed at the top of the five row calendar,
then the "worst case" is the first of a month on a Saturday and 31
days in the month.

In this case the last "week" in the month will consist of a Sunday the
30th and a Monday the 31st.  So you will only need two "split" tiles,
a 23/30 and a 24/31.

October 2005 will be just such a month.

If you were allowed to "rotate" the days of the week, then the days of
the month could always be fitted to five rows without using "splits". 
I admit to finding a calendar that changes the days of the week
around, e.g. business calendars that start on Mondays, confusing to
look at though.

regards, mathtalk-ga

Thanks so much! Yup, the days are fixed, and I don't think I could
stand it if they were moved around anyway! ;O) But that's all I
needed!