This problem offers you two ways to test reactions - use them to investigate your ideas about speeds of reaction.
Can you guess the colours of the 10 marbles in the bag? Can you develop an effective strategy for reaching 1000 points in the least number of rounds?
Can you coach your rowing eight to win?
Can you decode the mysterious markings on this ancient bone tool?
What information helped medical pioneers decide on the cause of a disease? Especially in a time before microscopes were as powerful as they are today ?
I need a figure for the fish population in a lake, how does it help to catch and mark 40 fish ?
Can you make a hypothesis to explain these ancient numbers?
The circumcentres of four triangles are joined to form a quadrilateral. What do you notice about this quadrilateral as the dynamic image changes? Can you prove your conjecture?
A good visualisation can be really useful when we need to convince ourselves that a probability calculation is correct. Here's a nice one.
Go to last month's problems to see more solutions.
This article explores the process of making and testing hypotheses.
An extra constraint means this Sudoku requires you to think in diagonals as well as horizontal and vertical lines and boxes of nine.