### Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

### Calendar Capers

Choose any three by three square of dates on a calendar page...

### 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...

# Doubly Symmetric

##### Stage: 3 Short Challenge Level:

What is the smallest number of additional squares that must be shaded so that this figure has at least one line of symmetry and rotational symmetry of order $2$?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

See all short problems arranged by curriculum topic in the short problems collection
This problem is taken from the UKMT Mathematical Challenges.