An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.
Choose any three by three square of dates on a calendar page...
Can you create a Latin Square from multiples of a six digit number?
Let the first term be x, then the sequence is x, 4, x+4, x+8, 2x+12. So 2x+12=22 and hence x=5.
This problem is taken from the UKMT Mathematical Challenges.