Palindromic decimal

1. Learning Contract Palindromic decimal By: Jing Han

2. Palindromic decimal • Palindromic comes from the word palindromes. • It is a number that remains the same when its digits are reversed. E.g. 24442, 69696

3. Palindromic decimals creation • Add to it’s reverse till you get a palindromic decimal. • Example: 9.7+7.9=17.6+6.71=24.31+13.42=37.73 • This palindromic decimals have 3 steps.

4. History Palindromes date back at least to 79 AD, as a palindrome was found as a graffito at Herculaneum, a city buried by ash in that year. This palindrome, called the Sator Square, consists of a sentence written in Latin: "SatorArepo Tenet Opera Rotas" ("The sower Arepo holds works wheels"). It is remarkable for the fact that the first letters of each word form the first word, the second letters form the second word, and so forth. Hence, it can be arranged into a word square that reads in four different ways: horizontally or vertically from either top left to bottom right or bottom right to top left. As such, they can be referred to as palindromatic.

5. Examples of palindromic decimals • 6.6 • 31.13 • 654.456 • 9696.6969 • 12345.54321 • 987654.456789 • 5123861.1683215 • 51235311.11353215

6. Questions • What is the next palindromic number after 1331? • How many different 5-digit palindromic numbers can be made using the digits 2, 5, 3, 5 and 3? • How many steps are required to produce a palindromic decimal starting with 3.52?

7. Solutions • 1441 • 2 (35253, 53235) • One step (3.52+25.3=28.82)

8. Refrences History page: http://en.wikipedia.org/wiki/Palindrome#History