Advent calendar 2016

6 December

When you add up the digits of a number, the result is called the digital sum.
How many different digital sums do the numbers from 1 to 1091 have?*
* There was a mistake in this question (it previously said 1092). If you answered the typo'd question right, your answer should automatically correct itself to 9 less than it was...


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


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


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