MT 007.02 / SL 266.01
Ideas in Mathematics: The Grammar of Numbers
Exercise 35: Calculating the date of Easter 1998

Does Gauss' formula, as presented here and in class, 'prove' that Easter 1998 falls on 12 April? Demonstrate this by computing the formula for 1998.

1. = MOD (J / 19)
2. = MOD (J / 4)
3. = MOD (J / 7)
4. = MOD ((19a + M) / 30 )
5. = MOD ((2b + 4c + 6d + N ) / 7 )

then P = ( 22 + d + e ) of March
unless P > 31,
in which case P = ( d + e - 9 ) of April.

Exceptions accounted for:

• If P = 26 April, then move P to 19 April (e.g. 1609, 1981, 2076, 2133)
• If P = 25 April
  and a > 10
  and d = 28,
  then move P to 18 April (e.g. 1954, 2049, 2106).

Presentation derived from Wislicenius, W.F.: Der Kalender. (Teubner) Leipzig, 1914(2). [Aus Natur und Geisteswelt, 69].

For this coming Wednesday's lecture material on Chinese numbers read Menninger pp.450-456.
Also follow any cross-references through, such as the reference to page 31 on classifiers.