2 December

Today's number is the area of the largest dodecagon that it's possible to fit inside a circle with area \(\displaystyle\frac{172\pi}3\).

Show answer

Cube multiples

Six different (strictly) positive integers are written on the faces of a cube. The sum of the numbers on any two adjacent faces is a multiple of 6.
What is the smallest possible sum of the six numbers?

Show answer & extension


Draw a regular polygon. Connect all its vertices to every other vertex. For example, if you picked a pentagon or a hexagon, the result would look as follows:
Colour the regions of your shape so that no two regions which share an edge are the same colour. (Regions which only meet at one point can be the same colour.)
What is the least number of colours which this can be done with?

Show answer & extension


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


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


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