Last lesson we looked at square numbers, so I thought it would be fun if we revisited Happy Numbers.
A happy number is a number for which the sum of the squares of the digits eventually equals 1. For instance, 203 is happy:
22 + 02 + 32 = 13
12 + 32 = 10
12 + 02 = 1.
Numbers that are not happy, such as 16, are called unhappy numbers.
In today’s lesson, we discovered that the following were ‘happy numbers’: 1, 7, 10, 13, 19, 23, 28, 31, 32.
Can you find any other happy numbers less than 100? How many are there?
Can you see a pattern?
Joseph said,
February 25, 2004 @ 3:10 am
I have searched the Internet but I can’t find this piece of info: Why are happy numbers called happy numbers? Why are they so happy? Who invented them and gave them this name? If anyone knows the answer, please email me at bwjyeo@nie.edu.sg and if possible, please provide some reliable references. Thanks.
Joseph