Summation of series

There are 32 NRICH Mathematical resources connected to Summation of series
A Swiss sum
problem

A Swiss sum

Age
16 to 18
Challenge level
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Can you use the given image to say something about the sum of an infinite series?
Vanishing point
problem

Vanishing point

Age
14 to 18
Challenge level
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How can visual patterns be used to prove sums of series?
Summing geometric progressions
problem

Summing geometric progressions

Age
14 to 18
Challenge level
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Watch the video to see how to sum the sequence. Can you adapt the method to sum other sequences?
Double Trouble
problem

Double Trouble

Age
14 to 16
Challenge level
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Simple additions can lead to intriguing results...
Speedy summations
problem

Speedy summations

Age
16 to 18
Challenge level
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Watch the video to see how to add together an arithmetic sequence of numbers efficiently.
Seriesly
problem

Seriesly

Age
16 to 18
Challenge level
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Prove that k.k! = (k+1)! - k! and sum the series 1.1! + 2.2! + 3.3! +...+n.n!
Googol
problem

Googol

Age
16 to 18
Challenge level
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Find the smallest value for which a particular sequence is greater than a googol.
Clickety Click
problem

Clickety Click

Age
16 to 18
Challenge level
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What is the sum of: 6 + 66 + 666 + 6666 ............+ 666666666...6 where there are n sixes in the last term?
Slick Summing
problem

Slick Summing

Age
14 to 16
Challenge level
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Watch the video to see how Charlie works out the sum. Can you adapt his method?
Summing squares
problem

Summing squares

Age
14 to 16
Challenge level
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Discover a way to sum square numbers by building cuboids from small cubes. Can you picture how the sequence will grow?