mscroggs.co.uk
mscroggs.co.uk

subscribe

Puzzles

Elastic numbers

Throughout this puzzle, expressions like \(AB\) will represent the digits of a number, not \(A\) multiplied by \(B\).
A two-digit number \(AB\) is called elastic if:
  1. \(A\) and \(B\) are both non-zero.
  2. The numbers \(A0B\), \(A00B\), \(A000B\), ... are all divisible by \(AB\).
There are three elastic numbers. Can you find them?

Show answer & extension

If you enjoyed this puzzle, check out Sunday Afternoon Maths LIX,
puzzles about digits, or a random puzzle.

Archive

Show me a random puzzle
 Most recent collections 

Advent calendar 2025

Advent calendar 2024

Advent calendar 2023

Advent calendar 2022


List of all puzzles

Tags

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

Archive

Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2026