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Advent calendar 2018
18 December
All 2018 advent puzzles
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There are 6 terms in the expansion of \((x+y+z)^2\):
$$(x+y+z)^2=x^2+y^2+z^2+2xy+2yz+2xz$$
Today's number is number of terms in the expansion of \((x+y+z)^{16}\).
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153
In general, the expansion of \((x+y+z)^n\) will have \(\frac12n(n-1)\) terms.
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addition
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ellipses
probability
averages
folding tube maps
advent
square grids
tangents
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perimeter
chalkdust crossnumber
polynomials
axes
medians
surds
xor
coordinates
angles
indices
cryptic crossnumbers
tiling
sets
cryptic clues
fractions
neighbours
consecutive numbers
floors
prime factors
lines
triangles
sequences
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graphs
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doubling
menace
trigonometry
multiplaction squares
decahedra
division
quadrilaterals
proportion
scales
polygons
pascal's triangle
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square numbers
integers
speed
gerrymandering
percentages
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multiples
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