#### You may also like

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.

### Weekly Problem 3 - 2013

Weekly Problem 3-2013

# Weekly Problem 2 - 2013

##### Stage: 3 Challenge Level:

Think of a number, double it, then add $3$. Multiply your answer by $4$ and from this take away $5$. Now also take away the number you first thought of.