problem A Swiss sum Age 16 to 18 Challenge level Can you use the given image to say something about the sum of an infinite series?
problem Vanishing point Age 14 to 18 Challenge level How can visual patterns be used to prove sums of series?
problem Summing geometric progressions Age 14 to 18 Challenge level Watch the video to see how to sum the sequence. Can you adapt the method to sum other sequences?
problem Double Trouble Age 14 to 16 Challenge level Simple additions can lead to intriguing results...
problem Speedy summations Age 16 to 18 Challenge level Watch the video to see how to add together an arithmetic sequence of numbers efficiently.
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 Googol Age 16 to 18 Challenge level Find the smallest value for which a particular sequence is greater than a googol.
problem Clickety Click 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 Slick Summing Age 14 to 16 Challenge level Watch the video to see how Charlie works out the sum. Can you adapt his method?
problem Summing squares Age 14 to 16 Challenge level Discover a way to sum square numbers by building cuboids from small cubes. Can you picture how the sequence will grow?