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...
Investigate how you can work out what day of the week your birthday will be on next year, and the year after...
$35$ teenagers were asked what takeaways they liked to eat.
None of the teenagers liked all three. All who liked pizza also liked Chinese and $9$ of the Chinese fans didn't like either Indian or pizza.
If all the teenagers liked at least one, how many liked only Indian?
If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.
This problem is taken from the UKMT Mathematical Challenges.