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Advent calendar 2015
17 December
All 2015 advent puzzles
~
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In March, I posted the puzzle
One Hundred Factorial
, which asked how many zeros 100! ends with.
What is the smallest number, n, such that n! ends with 50 zeros?
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205
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numbers
,
factorials
,
multiplication
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tangents
regular shapes
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symmetry
unit fractions
integration
probabilty
perfect numbers
quadratics
2d shapes
arrows
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rectangles
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chalkdust crossnumber
planes
geometry
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trigonometry
quadrilaterals
squares
polygons
perimeter
speed
balancing
doubling
proportion
consecutive integers
scales
fractions
geometric means
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graphs
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dodecagons
elections
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3d shapes
differentiation
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crosswords
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star numbers
cryptic clues
ave
matrices
mean
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folding tube maps
menace
games
hexagons
even numbers
expansions
multiplaction squares
factorials
integers
area
axes
cubics
people maths
money
averages
algebra
sport
sequences
division
digital clocks
tiling
remainders
probability
products
digits
ellipses
dates
neighbours
taxicab geometry
combinatorics
powers
logic
parabolas
complex numbers
albgebra
circles
angles
gerrymandering
sum to infinity
determinants
irreducible numbers
tournaments
shapes
factors
means
odd numbers
cube numbers
grids
square roots
sums
clocks
chess
binary
prime factors
colouring
xor
prime numbers
dominos
rugby
dice
coins
median
multiplication
volume
triangles
pentagons
geometric mean
cryptic crossnumbers
routes
lines
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