What is the sum of: 6 + 66 + 666 + 6666 ............+ 666666666...6 where there are n sixes in the last term?

Find the smallest value for which a particular sequence is greater than a googol.

Prove that k.k! = (k+1)! - k! and sum the series 1.1! + 2.2! + 3.3! +...+n.n!

The problem is how did Archimedes calculate the lengths of the sides of the polygons which needed him to be able to calculate square roots?

A weekly challenge concerning prime numbers.

Choose any whole number n, cube it and add 11n. Is the answer always divisible by 6? If so why?

This problem explores the biology behind Rudolph's glowing red nose.

Can you invert this confusing sentence from Lewis Carrol?

Our first weekly challenge. We kick off with a challenge concerning inequalities.

A weekly challenge concerning powers and quadratic equations.

A weekly challenge concerning the interpretation of an algorithm to determine the day on which you were born.

A weekly challenge: these are shorter problems aimed at Post-16 students or enthusiastic younger students.

A weekly challenge: these are shorter problems aimed at Post-16 students or enthusiastic younger students.

A weekly challenge: these are shorter problems aimed at Post-16 students or enthusiastic younger students.

Consider these weird universes and ways in which the stick man can shoot the robot in the back.

Can you massage the parameters of these curves to make them match as closely as possible?

Can you rotate a curve to make a volume of 1?

A weekly challenge concerning combinatorical probability.

A weekly challenge concerning trigonometry, circles and triangles.

A weekly challenge concerning statistics and averaging.

Find the location of the point of inflection of this cubic.

A weekly challenge: these are shorter problems aimed at Post-16 students or enthusiastic younger students. What has happened with my online integrator?