problem Succession in Randomia Age 16 to 18 Challenge level By tossing a coin one of three princes is chosen to be the next King of Randomia. Does each prince have an equal chance of taking the throne?
problem Harmonically Age 16 to 18 Challenge level Is it true that a large integer m can be taken such that: 1 + 1/2 + 1/3 + ... +1/m > 100 ?
problem Production Equation Age 16 to 18 Challenge level Each week a company produces X units and sells p per cent of its stock. How should the company plan its warehouse space?
problem Picturing Square Numbers Age 11 to 14 Challenge level Square numbers can be represented as the sum of consecutive odd numbers. What is the sum of 1 + 3 + ..... + 149 + 151 + 153?
problem Clickety Click and all the Sixes Age 16 to 18 Challenge level What is the sum of: 6 + 66 + 666 + 6666 ............+ 666666666...6 where there are n sixes in the last term?
problem Seriesly Age 16 to 18 Challenge level Prove that k.k! = (k+1)! - k! and sum the series 1.1! + 2.2! + 3.3! +...+n.n!
problem Reciprocal Triangles Age 16 to 18 Challenge level Prove that the sum of the reciprocals of the first n triangular numbers gets closer and closer to 2 as n grows.
problem More Polynomial Equations Age 16 to 18 Challenge level Find relationships between the polynomials a, b and c which are polynomials in n giving the sums of the first n natural numbers, squares and cubes respectively.
problem Picture Story Age 14 to 16 Challenge level Can you see how this picture illustrates the formula for the sum of the first six cube numbers?