### 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...

### Adding All Nine

Make a set of numbers that use all the digits from 1 to 9, once and once only. Add them up. The result is divisible by 9. Add each of the digits in the new number. What is their sum? Now try some other possibilities for yourself!

# Pair Sums

##### Age 11 to 14Challenge Level

Five numbers are added together in pairs to produce the following answers:

$0, 2, 4, 4, 6, 8, 9, 11, 13, 15$

What are the five numbers?