### 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...

# As Long as Possible

##### Age 11 to 14 ShortChallenge Level

The length of each side of a quadrilateral $ABCD$ is a whole number of centimetres. Given that $AB=4 \; \text{cm}$, $BC = 5 \; \text{cm}$ and $CD = 6 \; \text{cm}$, what is the maximum possible length of the fourth side $DA$?

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.
You can find more short problems, arranged by curriculum topic, in our short problems collection.