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List any 3 numbers. It is always possible to find a subset of adjacent numbers that add up to a multiple of 3. Can you explain why and prove it?

### Magic Sums and Products

How to build your own magic squares.

### No Matter

Weekly Problem 2 - 2013
After performing some operations, what number is your answer always a multiple of?

# Partitioning Revisited

##### Stage: 3 Challenge Level:

You may like to evaluate $(x + 4)^2, (x + 5)^2, (x + 6)^2$... before proceeding to $(x + a)^2$.