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 numbers, 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

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

Archive

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