mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Sum

What is
$$\sum_{i=1}^{\infty}\frac{1}{i 2^i}$$
?

Show answer & extension

If you enjoyed this puzzle, check out Sunday Afternoon Maths XXXIV,
puzzles about sum to infinity, or a random puzzle.

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2019

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

List of all puzzles

Tags

coordinates sum to infinity perimeter the only crossnumber taxicab geometry chalkdust crossnumber volume triangle numbers sums advent pascal's triangle perfect numbers wordplay graphs surds bases prime numbers colouring money ave elections tiling products arrows cryptic crossnumbers averages quadratics trigonometry multiplication dates square roots integers time digital clocks angles parabolas christmas odd numbers dodecagons multiples range functions partitions floors scales games factorials rectangles symmetry probabilty unit fractions squares triangles gerrymandering ellipses mean 3d shapes doubling balancing routes rugby lines logic 2d shapes area shape hexagons coins planes division cube numbers square numbers crossnumber differentiation shapes folding tube maps chess proportion crossnumbers spheres number irreducible numbers algebra factors people maths sport star numbers indices menace sequences digits remainders addition polygons probability regular shapes median cards geometry integration circles grids percentages means palindromes calculus cryptic clues speed fractions books dominos complex numbers numbers clocks crosswords chocolate dice

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2020