Sunday Afternoon Maths VII

 Posted on 2014-04-06 

Reverse bases

Find two digits \(a\) and \(b\) such that \(ab\) in base 10 is equal to \(ba\) in base 4.
Find two digits \(c\) and \(d\) such that \(cd\) in base 10 is equal to \(dc\) in base 7.
Find two digits \(e\) and \(f\) such that \(ef\) in base 9 is equal to \(fe\) in base 5.

Show answer & extension

Tags: numbers, bases

Ninety nine

In a 'ninety nine' shop, all items cost a number of pounds and 99 pence. Susanna spent £65.76. How many items did she buy?

Show answer & extension

Tags: numbers, money
If you enjoyed these puzzles, check out Advent calendar 2019,
puzzles about shape, or a random puzzle.


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


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


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