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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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,
factorials
,
multiplication
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List of all puzzles
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cards
odd numbers
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angles
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matrices
dice
chalkdust crossnumber
surds
area
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clocks
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3d shapes
xor
square numbers
shapes
rugby
numbers
volume
complex numbers
indices
rectangles
consecutive numbers
fractions
dominos
geometric means
2d shapes
crosswords
coins
cubics
cube numbers
differentiation
pentagons
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folding tube maps
sum to infinity
integers
ellipses
partitions
chess
irreducible numbers
neighbours
perfect numbers
integration
quadrilaterals
remainders
planes
christmas
polygons
palindromes
trigonometry
square roots
dates
proportion
grids
dodecagons
circles
division
elections
even numbers
chocolate
people maths
prime numbers
binary
taxicab geometry
square grids
perimeter
tiling
factorials
cryptic clues
sets
axes
calculus
determinants
sums
addition
multiplaction squares
factors
prime factors
speed
range
products
wordplay
balancing
colouring
expansions
probabilty
digital clocks
decahedra
geometric mean
menace
median
doubling
symmetry
powers
lines
tangents
sequences
money
combinatorics
algebra
bases
crossnumbers
gerrymandering
hexagons
number
multiplication
cryptic crossnumbers
arrows
star numbers
probability
unit fractions
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lists
averages
graphs
floors
parabolas
regular shapes
geometry
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quadratics
triangle numbers
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shape
digits
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means
sport
books
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time
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consecutive integers
tournaments
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pascal's triangle
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triangles
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