[ Music ]
>> Sponsored by the Institute
of Museum and Library Services.
>> Roswell Encina: Hi there,
and welcome to the 2021 Library
of Congress National
Book Festival.
I'm Roswell Encina, the
chief communication's officer
for the Library of Congress,
and we appreciate that all
of you have joined
us this afternoon.
We'll be talking with
author, comedian, math wizard,
and host Matt Parker
about his book "Humble Pi:
When Math Goes Wrong
in the Real World."
You'll have opportunities
to ask Matt your questions.
So start getting [inaudible]
and you send it our way
and I'll ask Matt
all your questions.
So let's get right to it.
Matt, welcome.
He's joining us from the
U.K. I should say, though,
I finished your book
last Friday.
It's like, you know, math
gone wild, math gone bad.
But before we get to
your book, you know,
the theme of the National
Book Festival is open a book,
open a world.
What books opened
the world to you?
>> Matt Parker: Oh wow.
Thank you very much for the kind
introduction as well, Roswell.
I've -- that's the first
time I've been introduced
as a math wizard, and I think I
will stipulate that from now on.
All my introductions
must be wizard based.
Highly appreciate that which
is not that far from my answer
to your next question
of [inaudible]
that kind of opened the world.
And I've, you know --
interesting situation because I
actually grew up in Australia.
I'm Australian.
I lived there for the first
couple decades of my life.
And then I moved to
the U.K where I am now.
And growing up in Australia
I used to read as a kid a lot
of fiction from around
the world,
and actually I should have --
because I read Encyclopedia
Brown.
That's the U.S series.
Something about a brother
-- my brother the big brain.
I forget the name of that.
So I've read like -- so a lot
of my impression as a child
in Australia who never traveled
to other countries was based
on the fiction I
read at the time.
And so growing up I read a lot
of Roald Dahl and Enid Blyton.
A lot of Enid Blyton
when I was much younger.
And when I moved to the U.K I
didn't realize how much I had
not distinguished
between what was
like the magic faraway
tree made up fantasy
and just literally England.
And so the first time I went
like to the seaside and they've
like literally got buckets
and pails and things,
I'm like, "Oh, my goodness."
This -- I had to work
out what was real
and what was fantasy
from growing.
And to this day I'm
still prising that apart.
So I feel like it -- my
childhood books reading,
Enid Blyton and Roald Dahl,
like opened the world
to me, but yeah.
I wasn't careful enough to work
out what could be
trusted and what couldn't.
>> Roswell Encina: I should say,
though, let's get to your book.
Your book opened my eyes
to a lot of math problems
that have gone on in
history I should say.
You know, you take a little
tongue in cheek approach
to the book, but a lot
of it's quite serious.
What was the genesis
of the book?
What made you think, "I
need to write about this."
>> Matt Parker: It
was because -- this --
"Humble Pi" is the
second book I wrote,
and the first book I wrote was
called "Things to Make and Do
in the Fourth Dimension."
And it was because as a
high school teacher my job,
prior to becoming an author
and comedian and wizard,
was finding engaging ways to
communicate math to people.
And so my first book
was very much aimed
at the already slightly
math curious semi nerd
where I could try and, you know,
communicate well there's amazing
like things in the
fourth dimension.
Really abstract bizarre
bits of mathematics.
And the book did well.
It did good for a math
book, average for a book.
And so my publisher
was like, "Okay.
What could we do if you want
to hit a wider audience?"
And I was like, "Oh, this is
-- this I'm interested in."
How can I find a vehicle where
a bigger range of people --
the less convinced proto nerds
will want to read the book.
I thought well everyone enjoys a
story of something going wrong.
And so I pitched a book.
I said, "Hey, what if I
write a book about all --
like the greatest math mistakes,
whenever math has
gone horribly wrong?"
And they're like,
"Oh, now that's --
that's something
people want to read."
And I'm thinking it's a great
excuse for me to then talk
about like -- by talking
about when it goes wrong,
I get to talk about the
incredible amount of math
which is holding our society
together that we never notice.
Or rather we only notice
when it does go wrong.
>> Roswell Encina:
I mean some of it --
keeping the world together.
Some of the math examples
that you made were literally,
you know, keeping things
together from bridges
to architecture to
the space shuttle
to just advertising campaigns.
You know, I kind of
joked about it earlier.
A lot of it is tongue in cheek,
but you know a miscalculation
could have
like very deadly consequences.
How were you able to balance the
fun and the serious in the book?
>> Matt Parker: Yeah.
That's an interesting one
because we were chatting
about this before that the book
was meant to be a comedy book
about mathematics, and that's
what I promised the publishers.
And then I'm like,
"Oh, my goodness.
There's like -- " In things
like, you know, engineering,
with bridges like you say,
medicine, well all sorts
of aerospace and planes, if
it goes wrong, people die.
And I was like I can't have like
every second story can't end
and then everybody died.
I've got to -- so
partly I was strategic
with what stories I put in.
So I can say actually of all the
aviation stories nobody dies.
So every story involving
a plane, if you're scared
of flying, I mean the book's not
going to help, but no one dies
in any of the plane stories.
And then when I did put in --
because I didn't want to shy
away from the seriousness.
It was just a case of
being careful when I put
in the stories where
people die, having a reason
for choosing those
specific stories
where I think there's
an important lesson,
and being respectful
looking at it.
So people died.
As well as obviously
engineering when bridges
and buildings collapse
which is pretty horrific.
Like there's been mistakes
where a simple line of code
that was wrong in some software
for a machine that was doing
like radiotherapy for
cancers caused multiple deaths
because of the way
the code was written.
And I was like that
is terrifying,
but I would be doing it a
service to not bring that up
and to make sure, you know,
on one hand I'm trying
to say it's fine to make
mistakes, we're all bad at math,
we're going to make mistakes,
but on the flip side sometimes
if it's a life or death
situation you've got
to get it right.
So I felt I had to put those in.
>> Roswell Encina: You didn't
hold any punches here with some
of the people or some of the I
guess examples that you used.
I mean you used NASA
as an example.
You used the U.K government.
From McDonald's to Pepsi
to British Airways,
what kind of reaction did
you get from these companies
and from these governments?
>> Matt Parker: You know what?
It was interesting --
and it was interesting
to see the difference
between private companies
and government agencies.
So anything with a private
company I never got anything
officially back from
a private company.
And so things like the Pepsi
case, and this was a case
where they miscalculated
a number in an --
>> Roswell Encina: I love this
[inaudible] much if you want
to kind of summarize
it for people watching.
That would be great.
>> Matt Parker: The short
version is they had an ad
in 1995 where if you collected
Pepsi points you could get
like a leather jacket or a
hat or these sorts of things.
I'm just seeing if I -- I
don't have that within reach.
I thought I might have some
of the images from that.
Oh, here we go.
You know what?
I can, if I get this
to work -- here we go.
So this is from the
commercial that ran in 1995.
If you collected 75 Pepsi
points you got a t-shirt.
If you collect 1,450
Pepsi points,
you get a leather jacket.
You can get some sunglasses.
It was the '90s.
Right? But then they wanted
to end the ad on a kind
of hilarious zany joke so
after the sunglasses they had
like a [inaudible] and for 7
million Pepsi points you could
get this military jet.
Ha. Ha. Ha.
It's all very funny.
However those jets at the time
cost the U.S military 20 million
U.S dollars.
And Pepsi points, as
long as you got enough
from a Pepsi container,
you could put
in a check for the rest.
And they were only
10 cents each.
So that jet would only cost you
$700,000 for a $20 million jet.
I have no idea what the resale
market is for these things,
but that's a good deal.
And so someone did it.
Someone filled in the
form, put in the check,
sent it off to Pepsi, had to go
to court and Pepsi had to argue
that the ad was clearly a joke
and it wasn't a serious
offer for a contract.
And they won the case.
They won the case.
But the whole thing was just
because when they were writing
the commercial they didn't stop
and think how much is a jet
worth, how much the points were.
They just thought,
"Oh, 7 million.
That's a big number."
And one of the themes
in the book is how our
brains are not naturally good
at doing math, particularly
big numbers.
That's one of my
favorite examples.
And so when it comes to big
numbers our brain will go,
"Oh, that's a big number.
That's a small number."
Relative sizes.
And it's not really wrong.
Our brains are -- and
it's nothing personal.
We're all bad at it.
And so when they're writing
this ad it's a nice simple
crisp example.
They were like, "Oh, 7
million, massive number."
Turns out the cost of the
jet, even bigger number.
And so they had to
take it to court.
They won. They changed the
commercial and all that.
But I couldn't get anything
official out of Pepsi.
So for something like
that it's only --
I was able to put it in the book
because the court like ruling
and the court case -- because
now it's legal precedent.
So good. I was able
to go and get all --
I had to dig through and find
all the court case results
and then go through
them whereas something
like NASA you were saying,
something where it's
a government thing,
there's a much more
of an obligation
to reveal what went wrong.
And so for the government ones
you could almost think there's a
bias that more things
go wrong in the military
and on government
contracts and with NASA
and with [inaudible] in Europe.
But it's just it's
selection bias because we hear
about those stories because
they're obliged to divulge them.
And so I'm digging
through pages and pages
of all these official inquiries
and investigations
going back some of them
to like I'm reading
inquiries from the 1800s
on why bridges collapsed
and all these things.
But it was all made
public and stays public
and you can see it whereas
what you don't see are the dark
stories like dark matter.
So there was one story I really
wanted to put in the book
and I knew about it because the
engineer involved was a friend
of mine.
And when I asked them, "Can
I put this in the book?"
They were like there was no way.
They're under so many
non disclosure agreements
and the company and
the contractors
and there was a 0% chance
for even quite a trivial
math mistake from one
of their projects that I
could put it in the book.
And so sadly a lot
of stuff that's done
by private companies
is simply not in there
because we either don't hear
about it, and if I did hear
about it it was so off the
record I couldn't put it
in the book.
>> Roswell Encina: You
know, what was aggravating
for me was whether they're
companies or governments,
you know, if somebody brings
up like a simple math mistake
that they did or, you know,
or something more elaborate,
they become so defensive.
And I like -- you wrote
something that kind
of sums everything up.
My main point was that there
is a general feeling in society
that math is not that important,
that it's okay not
to be good at it.
But so much of our economy
and technology requires
people who are good at math.
I mean I know this
stems from the --
you know the [inaudible]
in the U.K,
but I feel like people
are not --
despite it's a very serious
subject matter, you know,
I feel like math is
our universal language,
some people just don't
take it too seriously.
Even if it is something,
you know,
like an advertising campaign.
>> Matt Parker: And
a little bit of me
when I was writing the book
was me having flashbacks
to when I was a teacher.
So I taught teenagers
for several years.
When I was a high
school teacher,
and even during the training
students are always like,
"Why do we have to learn this?"
Which is fair enough.
Right? And parents
would say that as well.
"Why do my kids have
to learn this?
I'm terrible at math.
Of course they're bad at math."
I'm like don't give them
permission to be bad.
Like teenagers don't need any
help coming up with excuses.
But you see this from teenagers.
Why do we have to learn this?
And so part of what I was doing
with the book was like answering
that question like
once and for all.
And I'm -- hopefully it's
been a good resource and a lot
of teachers have now used this.
They can go through and find
examples before they teach,
you know, statistics
and averages,
before they teach triangles,
before they, you know,
teach numbers and log
scales and these things.
They can find examples of when
people didn't bother learning
that and things went
wrong as a consequence.
And so for me it was a
big part of the answer
to the why do I need
to know this.
And, as you say, just in general
I think it's so disappointing
that math has enabled
our society to do
such incredible technological
things, but it's always so good
at it and it's so
behind the scenes
that people don't even
realize the extent
to which their lives have
been bettered by math.
And the extent to which
we need more people
who are mathematicians or just
mathematically competent to go
in to these careers and
invent these new things
and keep the whole
system ticking over.
How important it is that
we have people going
through the math
education system,
coming out the other side,
becoming programmers, engineers,
researchers, scientists,
economists,
and all walks of life.
>> Roswell Encina: There's
been such a major push for STEM
in schools, especially here in
the U.S. What advice do you want
to give parents out there who
have, you know, kids at home
who have like -- who don't
love math or are very reluctant
to learn or just don't
have the drive to learn?
And I should say, though,
just reading this book it
does make it, you know,
very exciting, and just maybe
lays out the importance of math.
But how do you kind
of sell that to a kid?
>> Matt Parker: Yeah.
It's a tough sell, and I
think the biggest thing is,
as I mentioned in
passing a moment ago,
I distinctly remember being
in a parent teacher --
like on parent teacher night
talking to a parent of one
of my students who said
pretty much word for word,
"I'm not good at math
so of course my kid
isn't good at math."
And for me that's
like the opposite
of what you should be doing.
So at a minimum not actively
discouraging the child.
And that can be, you know,
deliberately or subconsciously.
The thing is math like is not as
hard as you remember it being.
Like it's the worst time in your
life to be forced to sit down
and learn mathematics
when you're a teenager.
You've got so many other things
and other priorities going on.
And so if you remember it
as being this incredibly
difficult thing,
it's not as bad as you remember.
And if you can have a positive
attitude, and if you can --
and be like, "Oh, you're right.
I also don't understand that,
but we can learn it together."
And all these things.
And one of the big
things I go on about is
that everyone finds
math difficult.
And acknowledging
that, accepting that,
and that not being an
excuse to not learn it,
like a lot of things you learn
that are important
are difficult.
But with mathematics because
everyone finds it difficult the
people who become
mathematicians, you know,
math enthusiasts,
us math wizards,
it's not because
we find math easy.
It's because we enjoy
the fact it's difficult.
And so that's an important
[inaudible] people miss.
They go, "Oh, people who are
good at math, they're different.
They find it easy."
No. They find it as
difficult as anyone else.
They've just they enjoy the
fact it's a challenge and,
like any kind of learning
a skill or exercising,
the more you do it, the
better you get at it.
And in math a lot of
it is accumulative.
Once you understand one bit,
then the next bit
is a lot easier,
and the next bit's a lot easier.
Whereas if you just
come slamming in halfway
up you find it incredibly
difficult.
So yeah. It's not as
hard as you remember,
and embrace the difficulty
and it's not an excuse
to let your kids off the hook.
>> Roswell Encina: I see
some questions coming
in so I just kind of want to
encourage our audience to keep
on sending your questions
and we're going
to get to them shortly.
I did mention just a few
minutes ago that I said
that math is maybe
like one of our --
like our universal language
understood around the world.
Then it just dawned on me like
here in the U.S we still use,
you know, English while the
rest of the world or most
of the world uses
the metric system.
There's one example in
your book if you want
to summarize it very quickly
too how it almost became very
disastrous, I should say, by
the weighing of pounds and kilos
when it came to a jet liner.
>> Matt Parker: Up
until then I'm
like this could be several
stories in the book, but yeah.
Mass and jet liner.
So there was an aircraft.
It was flight Air
Canada 173, I think.
Yeah. It was in the 1980s
and Canada had just switched
from imperial English
like traditional units
to the metric system.
And aircraft fuel is
not measured in volume.
It's measured in mass.
And that's because
if the temperature
of it changes, its
volume changes.
And so you've actually got --
you haven't got more
or less fuel.
It's just taking up
more or less space.
The mass stays the same.
And so this flight
they've calculated the mass
of fuel required to fly
from Edmonton to Montreal.
So a reasonable distance
across Canada.
However when they were
fueling it they --
instead of fueling
it in kilograms,
they fueled it in pounds.
And it's a conversion
of about 2ish, 2.2.
So it meant they accidentally
put in half as much fuel
as the flight would require.
And the long version of
the story is just insane.
Like all the things
-- number one.
All the things that
had to go wrong,
it was multiple technology and
math mistakes for this plane
to take off with half as
much fuel as it needed.
But then everything that
-- like no one died.
Just to recap.
Then what they did
like to survive it
and everyone was flying --
it's just an incredible story.
And for me I love it because
it's such a great example.
If students are ever like,
"Why do we have to learn --
" Like why do we have
to write our units?
Why do teachers go on and on
about what units is that in?
Well, this is why.
You get the units wrong,
suddenly you've got
over 80 people on an
aircraft with no fuel.
>> Roswell Encina: I
was asking you earlier.
You did your homework.
You know, when you go to each
case study here how much time
did that take?
And how much, you
know, work did that --
you know, you had to dig
through to, you know --
to find the real
answers of what happened.
>> Matt Parker: Yeah.
That's a -- it's interesting
because I also work doing videos
on YouTube and I work doing
shows and performances,
and I still do some work in
schools with young people.
I was dipping in and
out of writing this book
over the course of about
three years, give or take.
I reckon which is good
because, as I was saying before,
a lot of the research
just takes time.
Like I've got to -- for
some of it I'm like, "Oh,
I've got to find that report."
And the report is only
in certain libraries.
It's not been digitized yet.
And I've got to find a way
to get it scanned
and then sent to me.
And so a lot of it
is just I've got
to get the ball rolling early,
and then I can dip in and out
and then just keep the
research being bumped along.
So definitely not full
time, but it was three years
from beginning the research and
pulling these threads to see
where they lead to having
the finished research done
and the manuscript handed over
to a very relieved editor.
>> Roswell Encina: I bet.
I should say I was
very impressed.
Matt Parker's book
is "Humble Pi:
When Math Goes Wrong
in the Real World."
For everybody watching,
we do want to remind you
that there's a great resource
for teachers and students
on the library's website.
The link's up there
on your screen.
Let's get to some
questions here.
I think we have a question
from Neals Nielsen
[assumed spelling].
That's a name for you.
I love it.
His question is since we
all rely on calculators
and computers to do the math,
how can we learn to detect
when the answer is wrong?
>> Matt Parker: Yeah.
Great question, Neal [inaudible]
I'm going to simplify that.
It's true.
And people can get too
reliant on calculators,
and they don't do a sense check.
And there's different
degrees of sense checks.
So actually one of the stories
in the book is someone using
a calculator made a simple
calculation error.
And gave the wrong dose of
a medication to a patient,
and there was huge repercussions
just because they didn't stop
and think, "Does that
answer make sense?"
And again teachers go
on and on about this.
Do a sense check.
So one thing you can do is just
-- and like the technical name's
like an order of magnitude check
where you just think how big
are the numbers I'm multiplying
or dividing.
Roughly how big should
the answer be?
And just by -- even just off --
making you stop and think
that this makes sense.
I did that just today.
I had to do a calculation where
it was a ridiculous calculation.
Someone had sent in a
question to me asking --
I do a podcast where I
answer ridiculous problems
and questions and someone
said, "How long would a roll
of toilet paper be if it was
made of [inaudible] which is
like one molecule thick?"
And so this is of no level
of importance whatsoever.
If I get this answer wrong,
nothing is going to happen other
than I'll be mildly embarrassed
if someone points it out.
But I still did the whole
calculation properly
and calculated exactly, and
then I leant back and went,
well what should it be?
And I thought roughly what's
the thickness difference,
what's this, what's that.
And I just did like
a sense check
of is my answer roughly
the right size,
just to double check.
And the extreme version of
that is engineers will do --
it's called dimensional analysis
where you redo the
same calculation,
but instead of putting numbers
in it, you put units in it,
and all the equations and
formulae from engineering
and physics work just
as well with units
as they do with numbers.
And if you then do this as
like a parallel calculation,
and you make sure you get the
right units at the other side,
it's one more way of
checking that what you did
on the calculator was correct.
Good question.
>> Roswell Encina:
That is a great one.
So we have a question here
from Sarah [assumed spelling].
She's asking, "If you
could dispel one commonly
misunderstood thing about
math, what would it be?"
>> Matt Parker: Wow.
It would be -- I mean apart --
I've already gone on at adequate
length about how we're all bad
at math and blah, blah, blah.
Ignoring that one, it would be
that math is just about numbers
and people equate
math with arithmetic.
And that's like yes.
Arithmetic is part of math.
Don't get me wrong.
But it's like saying all
music is playing the piano.
And you're like yeah,
that's one part of it,
but there's so many
other ways to make music
than playing the piano.
And playing the piano
is wonderful,
but there are other things.
And for me that's how I feel
when people equate
math to just numbers.
I'm like no, but math is the
study -- like it's discovering,
enjoying, and exploiting
patterns.
That's mathematics.
And so I feel like it's a real
shame that so many people think
that math isn't like this
wonderful solving puzzles
discovering patterns
adventure that it is,
and they think it's just
adding together bigger
and bigger numbers.
>> Roswell Encina: We
have a question here
from Bob Perillo
[assumed spelling].
Let me pull out my glasses here.
He's asking, "Structured
programming has been
around for 50 years [inaudible]
languages like Ada and Rust.
Why have major software
projects been so [inaudible]?"
Bob is asking.
>> Matt Parker: Wow.
Great question, Bob.
It's a good point, and it's
because software is
written by humans.
And you're right.
Maybe we should have
like software --
so what Bob's saying is you've
got different languages you can
write computer code in just
like you've got different
languages you could write a
novel or a poem in.
Right? And they've all
got their pros and cons.
And so the ones here like
Ada and Rust are like solid
like robust, and some
languages it's more obvious
if there's a mistake
or something gone wrong
whereas personally I code a lot
in a language called Python.
If you want to look in to that.
Python is so many ways
things can go wrong.
But it's also super
user friendly.
And so obviously the two
prongs to why we have
so many software problems,
partly software is just insanely
complex and so interlinked,
and secondly it's written by
humans and constantly adapted.
And so the ESA example,
the European Space Agency,
they had an aircraft that
it was a mistake in the code
which caused the rocket on its
launch to suddenly veer off.
No humans.
It wasn't a staffed flight.
There were no humans on board.
It was actually it was a bunch
of spacecraft including my wife
is a space scientist and some
of her colleagues had a group
of satellites called the
cluster satellite on there.
And so they'd spent decades
working on this spacecraft
and then the thing blows up.
And so they were so sad.
But what had gone wrong is
basically it was a failure
of reusing code without
testing it properly.
That was it.
So it was partly human
nature to copy and paste,
and partly it's very difficult
to test for all edge cases.
And so they ported this code
from the previous rocket
and hadn't checked the
size of some values
that would going through it.
Yeah. So it exploded
over French Guinea
and they sent back the
crumpled bits of metal.
So in the coffee room
in the space science lab
where my wife works they've got
these charred bits of spacecraft
as a reminder that
one line of code
and all your hard work can
end up on fire in a swamp.
>> Roswell Encina: We do only
have a few more minutes here
so I'm going to combine
two questions here
that are very similar.
One is from Mary.
She's asking how can we all
help make math more relevant
to ordinary life.
And Roberts asking
something similar
like many learners avoid
math because it is black
and white meaning it's
right and wrong with no room
for errors with much red ink.
Discourages.
How do we increase
enjoyment of math?
So how do we make it relevant
to the -- our daily lives?
And how do we enjoy it more
on a daily basis I guess?
Combining these questions.
>> Matt Parker: I think
the answer to both is
to not be scared of it.
And so I know we've talked about
a bunch of terrifying, you know,
math goes wrong, everybody
dies or your rocket blows up
or whatever, but that's --
like there's a distinction
between math
when you're doing
something important and math
when you're messing around.
And so I think in terms of
everyday life people having --
I describe it as like
mathematical confidence.
So if you're, I don't
know, hiring a car,
and they offer you
insurance and you're like,
"Do I take it or not?"
Don't freak out because all
these numbers are coming at you.
Just have the confidence
to go, "No.
No. I can work this out."
And just relax.
I do that.
I'm like, "Hang on a second."
I get my phone out because
we've all got calculators
on our phones.
And I get a pen if I need to.
And I don't know the
answer straight away.
I can't do the math in my head.
But I've just got the confidence
to know I'll give it a
go and see what happens.
And actually in general just
give it a go there's all sorts
of fantastic math puzzles and
interesting investigations
and things you can do.
And so I work a lot as a
recreational mathematician
and that just means I'm
doing it for the sake of it.
I'm having fun.
I anticipate making
a lot of mistakes.
Math is more getting it wrong
than getting it right
by a long shot.
But that's because you're
learning things that are new
and you're trying to discover
things that are new to you.
>> Roswell Encina: I feel
like the answer's also
like what we -- when we're asked
how do we make our kids read
or how do we make people
[inaudible] the usual answer we
usually give is, you know,
make it fun, you know.
Do it at the checkout stand.
Do it, you know -- doing it
when you're on a road trip.
And just, you know, try to make
it more fun and make it less,
you know, textbook, and
very less intimidating.
We have time for
one more question.
I feel like this is the one
question everybody's dying
to ask you.
What is your favorite shape?
And when will we be getting
anymore user submitted
code videos?
And what is up with the
Christmas tree behind you?
>> Matt Parker: Favorite
shape is the [inaudible]
that was easy.
Over this -- behind me
this is my Christmas tree.
In hindsight I should have
moved it out of the background.
I programmed this
last Christmas.
It's got 500 lights on it, and
I mapped their 3D coordinates
and had 3D effects
going across it.
And the user submitted code
is because people sent in code
that I then ran on
my Christmas tree
because I open sourced
how it all worked.
So people sent in
code and I ran it
and this is what I love
about the internet.
I put a video out of just me
running other user submitted
code on my tree, and it's
had 4.9 million views.
And I love the fact --
everyone's like, "Oh,
math and technology and
programming is boring.
No one likes it.
It's a chore."
But we do stuff for fun and
5 million people can't --
maybe they can all be wrong.
I don't know.
But I love the fact that if you
told people before YouTube 5
million people would
watch me debug code
on my mathematical Christmas
tree, they wouldn't believe you.
But yet here we are.
>> Roswell Encina: Matt Parker,
the author of "Humble Pi:
When Math Goes Wrong
in the Real World."
We really appreciate it.
You really do make math fun.
As you mentioned, 5 million
viewers and counting,
and you're doing your
part to make math fun.
So we want to thank everyone
for, you know, participating
and watching on this
Sunday afternoon.
We greatly appreciate it.
This is day three of the
National Book Festival.
If you want to create your
own National Book Festival
experience, just go to our
website loc.gov/bookfest
and enjoy all the videos.
Again thank you, Matt.
And take care to everyone.
>> Matt Parker: Roswell,
thank you so much.
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