Some numbers are happy and others are not!
To find out whether a number is happy, square each of its digits, add the answers and repeat. If you end up with 1 the number is happy!
How many happy numbers can you find?
E.g. Consider 19
1^{2} + 9^{2} = 82
8^{2} + 2^{2} = 68
6^{2} + 8^{2} = 100
1^{2} + 0^{2} + 0^{2} = 1
This shows that 19 is a happy number.
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Topics: Starter  Arithmetic  Investigations
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Previous Day  This starter is for 25 January  Next Day
Casio Classwiz CalculatorThere is currently a lot of talk about this new calculator being the best in its price range for use in the Maths classroom. The new ClassWiz features a highresolution display making it easier to view numerical formulas and symbols but it isn't a graphical calculator as such (it has the capacity to draw graphs on your smart phone or tablet, via a scannable QR code and an app). As well as basic spreadsheet mode and an equation solving feature you also get the ability to solve quadratic, cubic or quartic polynomial inequalities and the answer is given just as it should be written down, using the correct inequality symbols! This calculator has a highperformance processor and twice the memory of previous models ensuring speedy operation and superior computational power.more... 
Teacher, do your students have
access to computers? 

Here a concise URL for a version of this page without the comments.
Transum.org/go/?Start=January25
Here is the URL which will take them to an interactive Happy Numbers activity.