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Advent calendar 2021
15 December
All 2021 advent puzzles
~
More information
The odd numbers are written in a pyramid.
(row 1)
1
(row 2)
3
5
(row 3)
7
9
11
etc.
What is the mean of the numbers in the 19th row?
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The mean of the numbers in the \(n\)th row is \(n^2\), so the mean of the number in the 19th row is
361
.
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percentages
balancing
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unit fractions
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sets
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volume
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shape
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time
square numbers
people maths
dominos
prime factors
rectangles
factors
coordinates
palindromes
perimeter
area
median
range
ave
quadratics
multiplication
expansions
wordplay
proportion
multiplaction squares
means
division
digital clocks
tiling
sport
prime numbers
polygons
calculus
sum to infinity
albgebra
crosswords
folding tube maps
consecutive integers
symmetry
remainders
ellipses
integration
dates
integers
combinatorics
cube numbers
complex numbers
christmas
sequences
odd numbers
digits
addition
even numbers
partitions
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spheres
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menace
consecutive numbers
scales
chocolate
colouring
xor
shapes
tournaments
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dodecagons
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bases
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lines
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