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


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


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