Great Easter activity in a Math lesson or a way of including Math in a Religious Studies lesson. How do we know when Easter Sunday is when it keeps moving every year? Easter never stays still, unlike Christmas there is not an exact date. How can we work out when Easter is each year? The date depends on both the Gregorian calendar (where there is a leap year every four years except for century years when it is only one in four) and the Jewish calendar (which follows a lunar cycle for years and months - it has a 19 year cycle where years 3, 6, 8, 11, 14 17 and 19 have a 13th month) In the Bible (St Luke, Chapter 22) we have a description of how Jesus ate the Passover with his disciples before going to Gethsemane. The Last Supper, the Agony in the Garden and the Crucifixion were at a time of a full moon following March 21st (Spring Equinox). The hurry to move the body before the beginning of the Jewish Sabbath (Saturday) fixes the Crucifixion on a Friday. The Church has sort to preserve this sequence. If only there was a Mathematical formula to find out . . . . There are extension opportunities for the most able and those with a keen eye for programming LICENSING TERMS: This purchase includes a license for one teacher only for personal use in their classroom. Licenses are non-transferable, meaning they cannot be passed from one teacher to another. No part of this resource is to be shared with colleagues or used by an entire grade level, school, or district without purchasing the proper number of licenses. COPYRIGHT TERMS: This resource may not be uploaded to the internet in any form, including classroom/personal websites or network drives, unless the site is password protected and can only be accessed by students.