# Happy Birthday NRICH!

## Happy Birthday NRICH!

To celebrate NRICH's 20th birthday, we are bringing together some rich mathematical activities that we think are 'hidden gems'.  You may not have come across these tasks before, perhaps because some of them are quite new, whereas others are rather old, but all of them are worth exploring.  Get your mathematical thinking hat on!

### Up and Down Staircases

##### Stage: 2 Challenge Level:

One block is needed to make an up-and-down staircase, with one step up and one step down. How many blocks would be needed to build an up-and-down staircase with 5 steps up and 5 steps down?

### Always, Sometimes or Never? Shape

##### Stage: 2 Challenge Level:

Are these statements always true, sometimes true or never true?

### Exploring Number Patterns You Make

##### Stage: 2 Challenge Level:

Explore Alex's number plumber. What questions would you like to ask? What do you think is happening to the numbers?

### Ice Cream

##### Stage: 2 Challenge Level:

You cannot choose a selection of ice cream flavours that includes totally what someone has already chosen. Have a go and find all the different ways in which seven children can have ice cream.