### 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...

# Triangle of Squares

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

The number at the end of the $n$th row is $n^{2}$,
so $400$ will lie at the end of the $20$th row.

The row below will end in $21^{2}$, i.e. $441$

So the number directly below $400$ will be $440$.

This problem is taken from the UKMT Mathematical Challenges.