The Blessing of the Sun (Birkat Hachamah) is a blessing recited once every 28 years, commemorating the work of Creation, and specifically the creation of the sun. It was observed this year, 5769, on the morning of April 8, 2009.
Now, many have noticed that the year number 5769 is not evenly divisible by 28. Dividing 5769 by 28 leaves a remainder of 1. One explanation that has been offered for the discrepancy, which appears to be a traditional explanation, says:
The Sages have already explained to us that during the year of the Flood, the natural order of the world was suspended.That may be so, but it has absolutely nothing to do with why the division leaves a remainder of one.
A better explanation is simple mathematics, and should be familiar to anyone who remembers the whole debate about whether the Millenium started in 2000 or 2001. (2001 is correct, even though it is not evenly divisible by 1000)