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Advent calendar 2018
11 December
All 2018 advent puzzles
~
More information
This puzzle is inspired by
a puzzle Woody showed me at MathsJam
.
Today's number is the number \(n\) such that $$\frac{216!\times215!\times214!\times...\times1!}{n!}$$ is a square number.
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By the same method as
this puzzle
, the answer is
108
.
Tags:
numbers
,
square numbers
,
factorials
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Most recent collections
Advent calendar 2025
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List of all puzzles
Tags
people maths
palindromes
proportion
geometric means
multiplication
crossnumbers
bases
sport
digital clocks
surds
quadrilaterals
triangles
cards
lists
integration
squares
taxicab geometry
rectangles
odd numbers
albgebra
even numbers
floors
lines
tiling
differentiation
cubics
square roots
median
dominos
range
unit fractions
coordinates
parabolas
digits
irreducible numbers
money
averages
chocolate
factorials
addition
partitions
quadratics
tournaments
advent
decahedra
hexagons
scales
multiplaction squares
triangle numbers
clocks
expansions
consecutive integers
percentages
neighbours
logic
routes
speed
algebra
prime numbers
coins
cryptic clues
gerrymandering
shape
square grids
perfect numbers
time
powers
crosswords
factors
sequences
2d shapes
star numbers
tangents
angles
dates
circles
functions
wordplay
dice
rugby
probabilty
pentagons
chalkdust crossnumber
games
probability
grids
multiples
regular shapes
means
remainders
number
graphs
products
area
planes
pascal's triangle
matrices
sums
division
shapes
christmas
perimeter
elections
dodecagons
binary
xor
integers
sets
ave
colouring
symmetry
prime factors
fractions
trigonometry
spheres
polygons
calculus
chess
mean
geometric mean
medians
books
square numbers
consecutive numbers
numbers
combinatorics
determinants
sum to infinity
cryptic crossnumbers
balancing
polynomials
complex numbers
axes
geometry
indices
volume
arrows
doubling
3d shapes
folding tube maps
the only crossnumber
cube numbers
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menace
digital products
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