Advent calendar 2018

17 December

For \(x\) and \(y\) between 1 and 9 (including 1 and 9), I write a number at the co-ordinate \((x,y)\): if \(x\lt y\), I write \(x\); if not, I write \(y\).
Today's number is the sum of the 81 numbers that I have written.

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Tags: numbers


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


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