23 December

Today's number is the area of the largest area rectangle with perimeter 46 and whose sides are all integer length.

Show answer

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

Squared circle

Each side of a square has a circle drawn on it as diameter. The square is also inscribed in a fifth circle as shown.
Find the ratio of the total area of the shaded crescents to the area of the square.

Show answer

Two triangles

Source: Maths Jam
The three sides of this triangle have been split into three equal parts and three lines have been added.
What is the area of the smaller blue triangle as a fraction of the area of the original large triangle?

Show answer & extension

Overlapping triangles

Four congruent triangles are drawn in a square.
The total area which the triangles overlap (red) is equal to the area they don't cover (blue). What proportion of the area of the large square does each (purple) triangle take up?

Show answer & extension

Unit octagon

The diagram shows a regular octagon with sides of length 1. The octagon is divided into regions by four diagonals. What is the difference between the area of the hatched region and the area of the region shaded grey?

Show answer & extension

Largest triangle

What is the largest area triangle which has one side of length 4cm and one of length 5cm?

Show answer & extension


Which is largest, the red or the blue area?

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


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


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