11 is a prime number.
1, 3, 4, 7, 11, 18, 29...
A Lucas number.
The Eleven Plus was an English school selection examination taken by 11 year olds which was abolished in most areas with the introduction of comprehensive schools. It is still fondly remembered by taxi drivers and education ministers.
Elevenses is a mid-morning refreshment such as tea and biscuits taken around 11am.
Soccer, cricket, American football and field hockey are all played with teams of 11 players on the field.
The sun spot cycle repeats about every 11 years. Sun spots are dark spots on the surface of the sun. They occur more often during the active phase of the sun spot cycle. The spots have intense magnetic fields which are associated with magnetic storms on earth. Radio reception on earth is also affected by the sun spot cycle.
In England the number 11 sometimes appears in the decoration of Easter cakes. The 11 almond paste decorations on this simnel cake represent the 12 apostles, but excluding the treacherous Judas Iscariot.
11 is the fourth number that stays the same when written upside down. The first three are 0, 1 and 8. Can you find the next three? They are all less than 100.