Amazing Old Calculator (Curta) - Numberphile

Alex's book: http://amzn.to/1l0yX46

The Curta is a pocket-sized, mechanical, digital calculator!!! It was invented by Curt Herzstark.

Shown here by Alex Bellos, author of Alex's Adventures in Numberland.

More about our contributors, including Alex, at http://www.numberphile.com/team/index.html

Website: http://www.numberphile.com/
Numberphile on Facebook: http://www.facebook.com/numberphile
Numberphile tweets: https://twitter.com/numberphile
Videos by Brady Haran

A run-down of Brady's channels:
http://periodicvideos.blogspot.co.uk/2012/06/here-are-my-channels.html

---

Closed Caption:


ALEX BELLOS: This is the Curta,
which is the only
mechanical pocket digital
calculator ever invented.
It was invented by Curt
Herzstark, who's an Austrian
engineer who had the
idea in the 1930s.
Because for the previous 300
years, there'd been this
desire for people to mechanize
calculating, because
calculating was quite
effortful.
It was quite difficult.
Wouldn't it be great if machines
could do it for us?
And the first person to have
this idea was Pascal in about
1650, who invented
the Pascaline.
And then Leibniz invented his
Step Reckoner, and et cetera,
et cetera, et cetera.
By the Victorian Age, there
were these big desk
calculators, where that's
where the phrase "number
crunching" comes from.
People would do these
complicated multiplications--
not complicated, just long
multiplications using machines.
But there was always the dream
to try and make it a bit more
user friendly, to make
a pocket-sized one.
But the challenge was to get the
right kind of engineering.
And Curt Herzstark in
the 1930s thought
he'd found a way.
But it took him another 20
years to develop it.
And one of the problems
was that the
second World War happened.
He was half Jewish, living in
Austria, so he was imprisoned
in the concentration camp.
But because he was quite a
well-known engineer, the Nazis
said we won't kill you.
We'll let you develop your
pocket calculate--
mechanical calculator.
They didn't kill him.
And I'm not sure if he hadn't
got there yet, or if he had
got there yet, but didn't want
to tell his Nazi captors.
Because very shortly after the
war when he was liberated, he
worked out how to do it.
And he tried to get
some investment.
It was quite difficult getting
investment for what was
essentially an executive toy.
And it was only in
Liechtenstein, the Dutch in
Liechtenstein, that the royal
family there invested in him.
And in the 1960s--
'50s and '60s--
about 100,000 of these
Curtas were made.
And they were very--
they're now a collector's
item.
I'm going to show you exactly
how they work.
You put the number down here,
your input number,
so I put there 68.
And when you turn this around,
it will add whatever number is
here on the sides to here, where
the output number comes.
So I put in 68.
I'm going to turn this around.
And you can see, it
goes to 68 there.
If I turn it around again, it
adds another 68, and another
68, and another 68.
And we can keep on going.
And now I've done
it five times.
So 5 times 68 is 340.
Because you might forget how
many times you've been turning
it around, there's a marker
here, 5, which reminds me that
I've put it around five times.
So it goes on to six, seven.
So 7 times 68 is 476.
It can do a whole lot
more than that.
Let's multiply by a
two-digit number.
Firstly, let's zero it, which
is quite good fun.
Zeroing it, you just pull
up and turn that around.
It's now completely zeroed.
BRADY HARAN: That's like
the clear button on a
calculator, isn't it?
ALEX BELLOS: Exactly.
It's the C. Then
you put this--
put these ones at the top.
So let's say we wanted
to say 24 times 33.
Let's put 24 here, 2
and then 4, so 33.
33, we need to multiply
three times--
one, two, three.
And then the clever thing
now is that we move it
from units to tens.
And we do another
three times--
one, two, three.
So we have multiplied it 33
times, three units, three on
the tens, and the
answer is 792.
It's a beautiful machine.
This is older than me.
It's 50 years old.
It looks brand new.
It's sturdy and tough.
And what was interesting about
it is in the '60s, it was a
toy, essentially, of rally
drivers and their copilots.
Because when you're a rally
driver, there are lots of
calculations you need
to do about
speeds, fuels, distances.
But if you had a slide rule,
you'd be slipping
all over the place.
Whereas with this, you could
do this and do the proper
calculations exactly.
And you're never
going to slip.
And it's just an absolutely
beautiful thing.
It was the zenith of the dream
of mechanizing calculation.
It was the end of the road.
It was the most perfect and
beautiful mechanized
calculator.
And then what happened
a few years later--
overtaken by electronic
calculation and calculators.
So this was as far as it got
along the road of mechanized
calculation.
I bought this on eBay.
You can get them for about 500
quid, although hopefully now,
it costs a little bit more.
So it's an investment.
Let's say we want to do--
I'll just pull these numbers.
What's this?
This is 3,242,333.
And just say I want to
multiply this by 678.
I will go 8--
three, four, five, six,
seven, eight.
One, two, three, four,
five, six, seven.
One, two, three, four,
five, six.
So 678 times 3,242,333
is 2,198,301,774.
BRADY HARAN: That's fun.
What were those little silver
things you moved around there
at the end?
ALEX BELLOS: These things here
are just where you would put
the commas, just to remind me.
These are like the commas.
That's all it is.
Every numberphile's
favorite toy.