mscroggs.co.uk
mscroggs.co.uk

subscribe

Advent calendar 2018

6 December

This puzzle is inspired by a puzzle that Daniel Griller showed me.
Write down the numbers from 12 to 22 (including 12 and 22). Under each number, write down its largest odd factor*.
Today's number is the sum of all these odd factors.
* If a number is odd, then its largest odd factor is the number itself.

Show answer

Archive

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

Tags

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

Archive

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