mscroggs.co.uk
mscroggs.co.uk

subscribe

Advent calendar 2020

24 December

There are six ways to put two tokens in a 3 by 3 grid so that the diagonal from the top left to the bottom right is a line of symmetry:
Today's number is the number of ways of placing two tokens in a 29 by 29 grid so that the diagonal from the top left to the bottom right is a line of symmetry.

Show answer

Archive

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

Tags

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

Archive

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