This is part of our Secondary Curriculum collection of favourite rich tasks arranged by topic.
Scroll down to see the complete collection, or explore our subcollections on Perimeter and Area in two dimensions, and Surface Area and Volume in three dimensions.

Your number is...
Think of a number and follow the machine's instructions... I know what your number is! Can you explain how I know?

The Number Jumbler
The Number Jumbler can always work out your chosen symbol. Can you work out how?

Special numbers
My two digit number is special because adding the sum of its digits to the product of its digits gives me my original number. What could my number be?

Number pyramids
Try entering different sets of numbers in the number pyramids. How does the total at the top change?

Crossed ends
Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?

Perimeter expressions
Create some shapes by combining two or more rectangles. What can you say about the areas and perimeters of the shapes you can make?

More number pyramids
When number pyramids have a sequence on the bottom layer, some interesting patterns emerge...

Always a multiple?
Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...


Fibonacci surprises
Play around with the Fibonacci sequence and discover some surprising results!


Think of two numbers
Think of two whole numbers under 10, and follow the steps. I can work out both your numbers very quickly. How?

Quadratic patterns
Surprising numerical patterns can be explained using algebra and diagrams...

You may also be interested in this collection of activities from the STEM Learning website, that complement the NRICH activities above.