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Days and Dates
Investigate how you can work out what day of the week your birthday will be on next year, and the year after...
DOTS Division
Take any pair of two digit numbers x=ab and y=cd where, without loss of generality, ab > cd . Form two 4 digit numbers r=abcd and s=cdab and calculate: {r^2 - s^2} /{x^2 - y^2}.
Age 11 to 16 Challenge Level:
Jo has three numbers which she adds together in pairs.
When she does this she has three different totals: $11$, $17$ and $22$
What are the three numbers Jo had to start with?
Can you describe a method that would enable you to work out the three numbers given any three totals?
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NRICH is part of the family of activities in the Millennium Mathematics Project.
NRICH is part of the family of activities in the Millennium Mathematics Project.