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



Lots of ones

Is any of the numbers 11, 111, 1111, 11111, ... a square number?

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What is the sum?

What is \(\displaystyle\frac{1}{\sqrt{1}+\sqrt{2}}+\frac{1}{\sqrt{2}+\sqrt{3}}+...+\frac{1}{\sqrt{15}+\sqrt{16}}\)?

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 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


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


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