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Comments in green were written by me. Comments in blue were not written by me.
2019-12-17
@
Rob
: It looks to me like you've made mistakes in questions 1, 6, 8, and 9. The hints from the back of the pdf might help:
1.
How many numbers between 1 and 10,000 have 1 as their final digit? How many have 1 as their penultimate digit?
6.
How many ways can you write 1? 2? 3? 4? 5? What's the pattern?
8.
How many zeros does 10! end in? How many zeros does 20! end in? How many zeros does 30! end in?
9.
Carol’s sum is odd. What does this tell you about the 5- and 6-digit numbers?
Matthew
on
/blog/70
×1
×1
×2
×1
×2
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Zines, pt. 2
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Dec 2023
Christmas card 2023
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Christmas (2023) is coming!
Zines
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TMiP 2023 puzzle hunt
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Chalkdust issue 17
Apr 2023
Logo Asteroids
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Mathsteroids on hyperbolic surfaces
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The databet
Jan 2023
Christmas (2022) is over
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Dec 2022
Off-by-one errors
Christmas card 2022
Nov 2022
Christmas (2022) is coming!
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24 Hour Maths Game Show
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Approximating π
Feb 2022
Build your own MENACE
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Christmas card 2021
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Christmas (2021) is coming!
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Close encounters of the second kind
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Christmas (2020) is over
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Christmas (2020) is coming!
Jul 2020
Happy τ-4 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 ▼
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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
frobel
mathsteroids
folding tube maps
platonic solids
determinants
interpolation
recursion
finite element method
big internet math-off
newcastle
advent calendar
london underground
arithmetic
python
weather station
sport
flexagons
dinosaurs
24 hour maths
machine learning
pythagoras
turtles
trigonometry
propositional calculus
accuracy
crossnumber
live stream
guest posts
speed
fonts
football
people maths
data visualisation
go
puzzles
errors
pizza cutting
reuleaux polygons
hexapawn
geometry
logs
inline code
craft
crochet
royal institution
tmip
pi
a gamut of games
anscombe's quartet
light
correlation
christmas
game of life
news
finite group
sorting
standard deviation
logic
chalkdust magazine
harriss spiral
tennis
fence posts
phd
cambridge
draughts
preconditioning
runge's phenomenon
quadrilaterals
mathslogicbot
exponential growth
noughts and crosses
matrices
manchester science festival
folding paper
youtube
mathsjam
matrix of minors
pac-man
ucl
javascript
braiding
sobolev spaces
dataset
rugby
nine men's morris
royal baby
wool
estimation
christmas card
databet
matrix of cofactors
weak imposition
european cup
realhats
talking maths in public
bempp
chess
mean
rhombicuboctahedron
programming
gaussian elimination
palindromes
world cup
signorini conditions
hannah fry
golden ratio
numbers
cross stitch
php
graphs
computational complexity
bodmas
simultaneous equations
bubble bobble
the aperiodical
game show probability
stickers
error bars
menace
misleading statistics
pi approximation day
datasaurus dozen
wave scattering
sound
asteroids
coins
polynomials
golden spiral
manchester
matt parker
convergence
squares
statistics
dates
edinburgh
curvature
electromagnetic field
numerical analysis
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reddit
latex
triangles
matrix multiplication
pascal's triangle
approximation
london
hats
logo
countdown
inverse matrices
radio 4
geogebra
map projections
national lottery
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games
video games
probability
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data
binary
ternary
chebyshev
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oeis
books
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martin gardner
hyperbolic surfaces
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captain scarlet
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zines
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stirling numbers
fractals
© Matthew Scroggs 2012–2024
1. How many numbers between 1 and 10,000 have 1 as their final digit? How many have 1 as their penultimate digit?
6. How many ways can you write 1? 2? 3? 4? 5? What's the pattern?
8. How many zeros does 10! end in? How many zeros does 20! end in? How many zeros does 30! end in?
9. Carol’s sum is odd. What does this tell you about the 5- and 6-digit numbers?
on /blog/70