4 December

There are 5 ways to tile a 3×2 rectangle with 2×2 squares and 2×1 dominos.
Today's number is the number of ways to tile a 9×2 rectangle with 2×2 squares and 2×1 dominos.

Show answer


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


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


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