Easter is the first Sunday after the first full moon after the vernal equinox, unless that falls on a Sunday in which case Easter is the following Sunday:

a = Y mod 19

b = Y / 100

c = Y mod 100

d = b / 4

e = b mod 4

f = (b + 8) / 25

g = (b - f + 1) / 3

h = (19 * a + b - d - g + 15) mod 30

i = c / 4

k = c mod 4

L = (32 + 2 * e + 2 * i - h - k) mod 7

m = (a + 11 * h + 22 * L) / 451

month = (h + L - 7 * m + 114) / 31

day = ((h + L - 7 * m + 114) mod 31) + 1

Note:

/  indicates integer division

• multiply

ex:  7/3 = 2    remainder 1   but we ignore the remainder     

       6/3 = 2    

       5/3 = 1

mod is module arithmetic - just returns the remainder

ex:  7 mod 3 is 1     7 mod 3 = 2 remainder 1 ( we just care about the remainder and ignore the quotient)

       6 mod 3 is  0   in this case we just care about the remainder of 0