### 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...

### Latin Numbers

Can you create a Latin Square from multiples of a six digit number?

# Contact Circles

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

Four touching circles all have radius 1 and their centres are at the corners of a square.

What is the radius of the circle through the points of contact $X, Y, Z$ and $T$?

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.
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