Advent calendar 2015

19 December

1 = 1/2 + 1/4 + 1/8 + 1/16 + 1/16. This is the sum of 5 unit fractions (the numerators are 1).
In how many different ways can 1 be written as the sum of 5 unit fractions? (the same fractions in a different order are considered the same sum.)


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


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


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