Advent calendar 2018

11 December

Today's number is the number \(n\) such that $$\frac{216!\times215!\times214!\times...\times1!}{n!}$$ is a square number.

Show answer


Show me a random puzzle
 Most recent collections 

Advent calendar 2020

Advent calendar 2019

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

List of all puzzles


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


Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2021