mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Sum

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

Show answer & extension

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

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

Archive

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