Show me a random puzzle
 Most recent collections 


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


Show me a random puzzle
▼ show ▼

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.)
© Matthew Scroggs 2019