Bird Watch
Stage: 2 and 3 Challenge Level: 
Do you know which birds are regular visitors where you live?
Terrariums
Stage: 3 Challenge Level:
Build a mini eco-system, and collect and interpret data on how well the plants grow under different conditions.
Big and Small Numbers in the Living World
Stage: 3 and 4 Challenge Level:
Work with numbers big and small to estimate and calculate various quantities in biological contexts.
Investigating Epidemics
Stage: 3 and 4 Challenge Level:
Simple models which help us to investigate how epidemics grow and die out.
Maths Is Everywhere!
Stage: 3 and 4 Challenge Level:
Maths is everywhere in the world! Take a look at these images. What mathematics can you see?
Capture and Recapture
Stage: 3 and 4 Challenge Level:
How do scientists or mathematicians estimate the size of a population of wild animals?
Robot Camera
Stage: 4 Challenge Level:
Could nanotechnology be used to see if an artery is blocked? Or is this just science fiction?
Using the Haemocytometer
Stage: 4 Challenge Level:
Practise your skills of proportional reasoning with this interactive haemocytometer.
Like Father Like Son
Stage: 4 Short Challenge Level:
What is the chance I will have a son who looks like me?
Counting Fish
Stage: 4 Challenge Level:
I need a figure for the fish population in a lake, how does it help to catch and mark 40 fish ?
Counting Dolphins
Stage: 4 Challenge Level:
How would you go about estimating populations of dolphins?
Big and Small Numbers in Biology
Stage: 4 Challenge Level:
Work with numbers big and small to estimate and calulate various quantities in biological contexts.
Biology Measurement Challenge
Stage: 4 Challenge Level:
Analyse these beautiful biological images and attempt to rank them in size order.
Time to Evolve
Stage: 4 Challenge Level:
How many generations would link an evolutionist to a very distant ancestor?
Influenza Virus: It's All in the Packaging
Stage: 4 and 5
This article explores how researchers in disease dynamics are using mathematics to understand how the influenza virus replicates.
Solving the Genome Puzzle
Stage: 4 and 5
The human genome is represented by a string of around 3 billion letters. To deal with such large numbers, genome sequencing relies on clever algorithms. This article investigates.
NRICH is part of the family of activities in the Millennium Mathematics Project.