Advent calendar 2015

17 December

In March, I posted the puzzle One Hundred Factorial, which asked how many zeros 100! ends with.
What is the smallest number, n, such that n! ends with 50 zeros?


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


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


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