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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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folding tube maps
menace
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chalkdust crossnumber
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elections
prime factors
fractions
axes
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integration
number
expansions
dominos
consecutive integers
percentages
multiplication
regular shapes
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even numbers
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integers
cube numbers
circles
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balancing
sets
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