Click here to win prizes by solving the puzzle Advent calendar.
Click here to win prizes by solving the puzzle Advent calendar.



Odd sums

What is \(\frac{1+3}{5+7}\)?
What is \(\frac{1+3+5}{7+9+11}\)?
What is \(\frac{1+3+5+7}{9+11+13+15}\)?
What is \(\frac{1+3+5+7+9}{11+13+15+17+19}\)?
What is \(\frac{\mathrm{sum\ of\ the\ first\ }n\mathrm{\ odd\ numbers}}{\mathrm{sum\ of\ the\ next\ }n\mathrm{\ odd\ numbers}}\)?

Show answer & extension

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


Show me a random puzzle
 Most recent collections 

Sunday Afternoon Maths LXVII

Coloured weights
Not Roman numerals

Advent calendar 2018

Sunday Afternoon Maths LXVI

Cryptic crossnumber #2

Sunday Afternoon Maths LXV

Cryptic crossnumber #1
Breaking Chocolate
Square and cube endings

List of all puzzles


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


Show me a random puzzle
▼ show ▼
© Matthew Scroggs 2012–2019