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problem
Next-door numbers
Florence, Ethan and Alma have each added together two 'next-door' numbers. What is the same about their answers?
problem
Tetra inequalities
Can you prove that in every tetrahedron there is a vertex where the three edges meeting at that vertex have lengths which could be the sides of a triangle?
problem
Favourite
Cubes within cubes revisited
Imagine starting with one yellow cube and covering it all over with
a single layer of red cubes, and then covering that cube with a
layer of blue cubes. How many red and blue cubes would you need?
problem
The clockmaker's birthday cake
The clockmaker's wife cut up his birthday cake to look like a clock
face. Can you work out who received each piece?
problem
Hot pursuit
I added together the first 'n' positive integers and found that my answer was a 3 digit number in which all the digits were the same...
problem
Multiple magic
Think of any whole number. Each time you perform a sequence of operations on it, what do you notice about the divisors of your answer?
problem
Dilution series calculator
Which dilutions can you make using 10ml pipettes and 100ml measuring cylinders?
problem
Favourite
Impossibilities
Just because a problem is impossible doesn't mean it's difficult...
problem
Favourite
Three neighbours
Take three consecutive numbers and add them together. What do you notice?