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


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


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