mscroggs
.co.uk
mscroggs
.co.uk
blog
puzzles
academic
talks
contact
subscribe
↓ ☰ ↓
subscribe
Loading image...
Comment
Comments
Comments in green were written by me. Comments in blue were not written by me.
2024-12-19
Matt, great card this year! Problems 1 and 2 are slightly ambiguous though in that you did not specify that each digit could only be used once.
I initially thought the answers were simply 44×44 = 1936 and 99×99999999 = 9899999901, respectively ????
Dan Whitman
on
/blog/112
×1
×1
Archive
Show me a random blog post
2026
May 2026
World Cup stickers 2026
Apr 2026
A new puzzle every day
Mixing Wordle with other games
Feb 2026
Christmas (2025) is over
2025
Dec 2025
Christmas card 2025
Nov 2025
Christmas (2025) is coming!
Sep 2025
The partridge puzzle
Aug 2025
TMiP 2025 puzzle hunt
Jun 2025
A nonogram alphabet
Mar 2025
How to write a crossnumber
Jan 2025
Christmas (2024) is over
Friendly squares
2024
Dec 2024
A regular expression Christmas puzzle
Christmas card 2024
Nov 2024
Christmas (2024) is coming!
Feb 2024
Zines, pt. 2
Jan 2024
Christmas (2023) is over
2023
▼ show ▼
▲ hide ▲
Dec 2023
Christmas card 2023
Nov 2023
Christmas (2023) is coming!
Zines
Sep 2023
TMiP 2023 puzzle hunt
May 2023
Chalkdust issue 17
Apr 2023
Logo Asteroids
Mar 2023
Mathsteroids on hyperbolic surfaces
Feb 2023
The databet
Jan 2023
Christmas (2022) is over
2022
▼ show ▼
▲ hide ▲
Dec 2022
Off-by-one errors
Christmas card 2022
Nov 2022
Christmas (2022) is coming!
Oct 2022
24 Hour Maths Game Show
Mar 2022
Approximating π
Feb 2022
Build your own MENACE
Jan 2022
Christmas (2021) is over
2021
▼ show ▼
▲ hide ▲
Dec 2021
Christmas card 2021
Nov 2021
Christmas (2021) is coming!
Sep 2021
TMiP 2021 puzzle hunt
May 2021
Close encounters of the second kind
Jan 2021
Christmas (2020) is over
2020
▼ show ▼
▲ hide ▲
Dec 2020
Christmas card 2020
Nov 2020
Christmas (2020) is coming!
Jul 2020
Happy -3+τ-φ Approximation Day!
May 2020
A surprising fact about quadrilaterals
Interesting tautologies
Mar 2020
Log-scaled axes
Feb 2020
PhD thesis, chapter ∞
PhD thesis, chapter 5
PhD thesis, chapter 4
PhD thesis, chapter 3
Inverting a matrix
PhD thesis, chapter 2
Jan 2020
PhD thesis, chapter 1
Gaussian elimination
Matrix multiplication
Christmas (2019) is over
2019
▼ show ▼
▲ hide ▲
Dec 2019
Visualising MENACE's learning
Christmas card 2019
Nov 2019
Christmas (2019) is coming!
Sep 2019
A non-converging LaTeX document
TMiP 2019 treasure punt
Jul 2019
Big Internet Math-Off stickers 2019
Jun 2019
Proving a conjecture
Apr 2019
Harriss and other spirals
Mar 2019
realhats
Jan 2019
Christmas (2018) is over
2018
▼ show ▼
▲ hide ▲
Dec 2018
Christmas cross stitch
MENACE in fiction
Christmas card 2018
Nov 2018
Christmas (2018) is coming!
Sep 2018
Runge's Phenomenon
Jul 2018
World Cup stickers 2018, pt. 3
Mathsteroids
Jun 2018
World Cup stickers 2018, pt. 2
May 2018
A bad Puzzle for Today
Apr 2018
Building MENACEs for other games
Mar 2018
A 20,000-to-1 baby?
World Cup stickers 2018
Jan 2018
Origins of World War I
Christmas (2017) is over
2017
▼ show ▼
▲ hide ▲
Dec 2017
Christmas card 2017
Nov 2017
Christmas (2017) is coming!
MENACE at Manchester Science Festival
Jun 2017
Big Ben Strikes Again
Mar 2017
The end of coins of constant width
Dragon curves II
Feb 2017
The importance of estimation error
Jan 2017
Is MEDUSA the new BODMAS?
2016
▼ show ▼
▲ hide ▲
Dec 2016
Christmas (2016) is over
Video game surfaces
Christmas card 2016
Nov 2016
Christmas (2016) is coming!
Oct 2016
Logical contradictions
Palindromic dates
Sep 2016
Tube map kaleidocycles
Jul 2016
Solving the cross diagonal cover problem
Jun 2016
Braiding, pt. 2
Braiding, pt. 1
Making names in Life
May 2016
Euro 2016 stickers
Mar 2016
Proving Pythagoras' theorem
Dragon curves
The
Mathematical Games
of Martin Gardner
Jan 2016
Christmas (2015) is over
2015
▼ show ▼
▲ hide ▲
Nov 2015
Christmas (2015) is coming!
Oct 2015
How to kick a conversion
How much will I win on the new National Lottery?
Aug 2015
How OEISbot works
MENACE
Mar 2015
Optimal Pac-Man
Tube map stellated rhombicuboctahedron
Logic bot, pt. 2
Design your own flexagon
Jan 2015
Tube map Platonic solids, pt. 3
2014
▼ show ▼
▲ hide ▲
Nov 2014
Logic bot
Sep 2014
Electromagnetic Field talk
Jun 2014
Tennis maths
May 2014
World Cup stickers
Apr 2014
Countdown probability, pt. 2
Countdown probability
Mar 2014
New machine unfriendly £1 coin, pt. 2
New machine unfriendly £1 coin
2013
▼ show ▼
▲ hide ▲
Dec 2013
Assorted christmaths
Pointless probability
Jul 2013
"Uncanny" royal coincidence
Raspberry Pi weather station
2012
▼ show ▼
▲ hide ▲
Nov 2012
Tube map Platonic solids, pt. 2
Oct 2012
Tube map Platonic solids
Tags
programming
bots
pi
javascript
exponential growth
crossnumbers
manchester science festival
misleading statistics
ucl
nine men's morris
arithmetic
error bars
rugby
electromagnetic field
london underground
pac-man
tennis
binary
books
gaussian elimination
pokémon
regular expressions
sorting
hexapawn
stickers
pokémon wordle
matrices
wool
finite group
harriss spiral
dates
pi approximation day
live stream
bempp
dataset
realhats
hats
martin gardner
errors
convergence
mean
tetris
sound
countdown
world cup
newcastle
games
chebyshev
royal baby
accuracy
light
squares
the aperiodical
weather station
news
logs
go
oeis
mathsteroids
royal institution
preconditioning
cross stitch
bubble bobble
wordle
golden spiral
draughts
rhombicuboctahedron
advent calendar
latex
golden ratio
pascal's triangle
runge's phenomenon
friendly squares
london
numbers
ternary
turtles
boundary element methods
bodmas
finite element method
dinosaurs
graph theory
bluesky
computational complexity
frobel
interpolation
graphs
puzzles
people maths
nonograms
game of life
crosswords
dragon curves
24 hour maths
matrix multiplication
gather town
video games
sport
christmas
crochet
recursion
palindromes
quadrilaterals
folding paper
map projections
databet
triangles
braiding
gerry anderson
zines
approximation
talking maths in public
matrix of cofactors
determinants
hyperbolic surfaces
crossnumber
a gamut of games
php
machine learning
speed
rust
mathslogicbot
manchester
big internet math-off
matrix of minors
football
coins
data visualisation
kings
plastic ratio
inline code
correlation
sobolev spaces
fractals
statistics
flexagons
hannah fry
guest posts
menace
european cup
folding tube maps
asteroids
raspberry pi
numerical analysis
cambridge
christmas card
anscombe's quartet
estimation
wave scattering
thirteen
reuleaux polygons
python
trigonometry
reddit
propositional calculus
standard deviation
signorini conditions
weak imposition
phd
data
fence posts
game show probability
matt parker
chess
youtube
pizza cutting
polynomials
noughts and crosses
logo
final fantasy
curvature
national lottery
captain scarlet
pythagoras
geometry
logic
probability
arrangement puzzles
geogebra
stirling numbers
radio 4
datasaurus dozen
coventry
tmip
platonic solids
chalkdust magazine
simultaneous equations
warwick
inverse matrices
edinburgh
mathsjam
fonts
partridge puzzle
kenilworth
alphabets
craft
Archive
Show me a random blog post
▼ show ▼
▲ hide ▲
2026
May 2026
World Cup stickers 2026
Apr 2026
A new puzzle every day
Mixing Wordle with other games
Feb 2026
Christmas (2025) is over
2025
Dec 2025
Christmas card 2025
Nov 2025
Christmas (2025) is coming!
Sep 2025
The partridge puzzle
Aug 2025
TMiP 2025 puzzle hunt
Jun 2025
A nonogram alphabet
Mar 2025
How to write a crossnumber
Jan 2025
Christmas (2024) is over
Friendly squares
2024
Dec 2024
A regular expression Christmas puzzle
Christmas card 2024
Nov 2024
Christmas (2024) is coming!
Feb 2024
Zines, pt. 2
Jan 2024
Christmas (2023) is over
2023
▼ show ▼
▲ hide ▲
Dec 2023
Christmas card 2023
Nov 2023
Christmas (2023) is coming!
Zines
Sep 2023
TMiP 2023 puzzle hunt
May 2023
Chalkdust issue 17
Apr 2023
Logo Asteroids
Mar 2023
Mathsteroids on hyperbolic surfaces
Feb 2023
The databet
Jan 2023
Christmas (2022) is over
2022
▼ show ▼
▲ hide ▲
Dec 2022
Off-by-one errors
Christmas card 2022
Nov 2022
Christmas (2022) is coming!
Oct 2022
24 Hour Maths Game Show
Mar 2022
Approximating π
Feb 2022
Build your own MENACE
Jan 2022
Christmas (2021) is over
2021
▼ show ▼
▲ hide ▲
Dec 2021
Christmas card 2021
Nov 2021
Christmas (2021) is coming!
Sep 2021
TMiP 2021 puzzle hunt
May 2021
Close encounters of the second kind
Jan 2021
Christmas (2020) is over
2020
▼ show ▼
▲ hide ▲
Dec 2020
Christmas card 2020
Nov 2020
Christmas (2020) is coming!
Jul 2020
Happy -3+τ-φ Approximation Day!
May 2020
A surprising fact about quadrilaterals
Interesting tautologies
Mar 2020
Log-scaled axes
Feb 2020
PhD thesis, chapter ∞
PhD thesis, chapter 5
PhD thesis, chapter 4
PhD thesis, chapter 3
Inverting a matrix
PhD thesis, chapter 2
Jan 2020
PhD thesis, chapter 1
Gaussian elimination
Matrix multiplication
Christmas (2019) is over
2019
▼ show ▼
▲ hide ▲
Dec 2019
Visualising MENACE's learning
Christmas card 2019
Nov 2019
Christmas (2019) is coming!
Sep 2019
A non-converging LaTeX document
TMiP 2019 treasure punt
Jul 2019
Big Internet Math-Off stickers 2019
Jun 2019
Proving a conjecture
Apr 2019
Harriss and other spirals
Mar 2019
realhats
Jan 2019
Christmas (2018) is over
2018
▼ show ▼
▲ hide ▲
Dec 2018
Christmas cross stitch
MENACE in fiction
Christmas card 2018
Nov 2018
Christmas (2018) is coming!
Sep 2018
Runge's Phenomenon
Jul 2018
World Cup stickers 2018, pt. 3
Mathsteroids
Jun 2018
World Cup stickers 2018, pt. 2
May 2018
A bad Puzzle for Today
Apr 2018
Building MENACEs for other games
Mar 2018
A 20,000-to-1 baby?
World Cup stickers 2018
Jan 2018
Origins of World War I
Christmas (2017) is over
2017
▼ show ▼
▲ hide ▲
Dec 2017
Christmas card 2017
Nov 2017
Christmas (2017) is coming!
MENACE at Manchester Science Festival
Jun 2017
Big Ben Strikes Again
Mar 2017
The end of coins of constant width
Dragon curves II
Feb 2017
The importance of estimation error
Jan 2017
Is MEDUSA the new BODMAS?
2016
▼ show ▼
▲ hide ▲
Dec 2016
Christmas (2016) is over
Video game surfaces
Christmas card 2016
Nov 2016
Christmas (2016) is coming!
Oct 2016
Logical contradictions
Palindromic dates
Sep 2016
Tube map kaleidocycles
Jul 2016
Solving the cross diagonal cover problem
Jun 2016
Braiding, pt. 2
Braiding, pt. 1
Making names in Life
May 2016
Euro 2016 stickers
Mar 2016
Proving Pythagoras' theorem
Dragon curves
The
Mathematical Games
of Martin Gardner
Jan 2016
Christmas (2015) is over
2015
▼ show ▼
▲ hide ▲
Nov 2015
Christmas (2015) is coming!
Oct 2015
How to kick a conversion
How much will I win on the new National Lottery?
Aug 2015
How OEISbot works
MENACE
Mar 2015
Optimal Pac-Man
Tube map stellated rhombicuboctahedron
Logic bot, pt. 2
Design your own flexagon
Jan 2015
Tube map Platonic solids, pt. 3
2014
▼ show ▼
▲ hide ▲
Nov 2014
Logic bot
Sep 2014
Electromagnetic Field talk
Jun 2014
Tennis maths
May 2014
World Cup stickers
Apr 2014
Countdown probability, pt. 2
Countdown probability
Mar 2014
New machine unfriendly £1 coin, pt. 2
New machine unfriendly £1 coin
2013
▼ show ▼
▲ hide ▲
Dec 2013
Assorted christmaths
Pointless probability
Jul 2013
"Uncanny" royal coincidence
Raspberry Pi weather station
2012
▼ show ▼
▲ hide ▲
Nov 2012
Tube map Platonic solids, pt. 2
Oct 2012
Tube map Platonic solids
Tags
turtles
world cup
matrix multiplication
gaussian elimination
boundary element methods
php
christmas
gather town
electromagnetic field
finite group
warwick
european cup
royal baby
weak imposition
craft
propositional calculus
chebyshev
books
gerry anderson
arrangement puzzles
matt parker
hexapawn
hannah fry
youtube
misleading statistics
stirling numbers
pi approximation day
geometry
manchester science festival
approximation
logo
anscombe's quartet
fence posts
tennis
python
bodmas
databet
squares
map projections
tetris
countdown
hats
hyperbolic surfaces
datasaurus dozen
sound
plastic ratio
accuracy
signorini conditions
cambridge
martin gardner
the aperiodical
correlation
mean
palindromes
data visualisation
noughts and crosses
logs
exponential growth
raspberry pi
rust
javascript
data
dates
matrix of cofactors
ternary
pythagoras
nonograms
graph theory
polynomials
trigonometry
news
sobolev spaces
wool
runge's phenomenon
speed
determinants
graphs
pizza cutting
live stream
christmas card
advent calendar
ucl
newcastle
a gamut of games
arithmetic
alphabets
mathsteroids
partridge puzzle
friendly squares
errors
curvature
cross stitch
crossnumber
kings
wordle
reuleaux polygons
24 hour maths
game of life
frobel
big internet math-off
captain scarlet
preconditioning
fractals
mathsjam
pascal's triangle
latex
wave scattering
london
fonts
statistics
interpolation
tmip
crossnumbers
machine learning
chess
probability
crochet
regular expressions
asteroids
error bars
stickers
draughts
bluesky
folding tube maps
bempp
dragon curves
flexagons
inverse matrices
pi
royal institution
final fantasy
rugby
kenilworth
geogebra
games
bubble bobble
logic
inline code
edinburgh
puzzles
simultaneous equations
triangles
national lottery
crosswords
braiding
numerical analysis
convergence
rhombicuboctahedron
go
pokémon wordle
light
dinosaurs
people maths
guest posts
video games
computational complexity
zines
thirteen
platonic solids
finite element method
programming
matrix of minors
quadrilaterals
menace
bots
chalkdust magazine
sport
football
weather station
realhats
phd
pac-man
radio 4
golden ratio
folding paper
sorting
golden spiral
binary
game show probability
numbers
manchester
standard deviation
recursion
nine men's morris
harriss spiral
oeis
matrices
london underground
mathslogicbot
talking maths in public
reddit
estimation
coins
pokémon
dataset
coventry
© Matthew Scroggs 2012–2026
I initially thought the answers were simply 44×44 = 1936 and 99×99999999 = 9899999901, respectively ????
on /blog/112