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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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Christmas (2023) is coming!
Zines
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TMiP 2023 puzzle hunt
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Chalkdust issue 17
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Logo Asteroids
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Mathsteroids on hyperbolic surfaces
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The databet
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Christmas (2022) is over
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Dec 2022
Off-by-one errors
Christmas card 2022
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Christmas (2022) is coming!
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24 Hour Maths Game Show
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Approximating π
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Build your own MENACE
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Christmas (2021) is coming!
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Christmas (2020) is coming!
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Happy (ϕ+τ)-√2 Approximation Day!
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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 ▼
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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
captain scarlet
correlation
quadrilaterals
interpolation
data
chebyshev
manchester
graphs
triangles
draughts
latex
royal baby
wool
error bars
javascript
live stream
dinosaurs
london underground
bubble bobble
php
polynomials
mathsteroids
numerical analysis
machine learning
speed
stickers
pac-man
logic
palindromes
dates
news
nine men's morris
realhats
go
programming
computational complexity
london
cross stitch
matrix of cofactors
european cup
guest posts
platonic solids
sound
rhombicuboctahedron
preconditioning
noughts and crosses
plastic ratio
asteroids
fonts
stirling numbers
video games
logs
statistics
inverse matrices
pizza cutting
books
crossnumber
world cup
menace
simultaneous equations
wave scattering
crochet
exponential growth
christmas
advent calendar
24 hour maths
hannah fry
game of life
radio 4
folding paper
chalkdust magazine
big internet math-off
pascal's triangle
estimation
talking maths in public
determinants
datasaurus dozen
game show probability
national lottery
accuracy
arithmetic
boundary element methods
matrix multiplication
squares
runge's phenomenon
graph theory
convergence
final fantasy
gerry anderson
finite group
golden ratio
tennis
pythagoras
errors
data visualisation
people maths
coins
binary
sobolev spaces
inline code
christmas card
matrices
zines
hats
royal institution
puzzles
dataset
chess
dragon curves
probability
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craft
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frobel
harriss spiral
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a gamut of games
martin gardner
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anscombe's quartet
newcastle
weather station
geometry
misleading statistics
map projections
folding tube maps
bodmas
curvature
raspberry pi
bempp
ternary
geogebra
rugby
tmip
propositional calculus
braiding
the aperiodical
logo
reuleaux polygons
pi approximation day
games
cambridge
recursion
hyperbolic surfaces
finite element method
fence posts
hexapawn
flexagons
databet
matrix of minors
golden spiral
manchester science festival
edinburgh
weak imposition
sorting
ucl
approximation
gaussian elimination
trigonometry
matt parker
signorini conditions
standard deviation
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oeis
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phd
numbers
light
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gather town
© 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