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Well where is the decimal system used?
Well that is used in physics like a metric system, right? In engineering.
So we have what?
Meters, right?
The base unit meter and then you go kilometer.
And that is what? Meter times ...
Student: Thousand [...].
Times one hundred? Right?
And then [...] something else, right?
And ...
Centimeter ...
... is meter times ...
Or how many centimeters are there in one meter?
One hundred?
And there is millimeter.
How many millimeters are there in one centimeter?
Student: Ten. NB: Ten.
OK. So you know that but er ...
[...] is that not everything is named.
But whatever is named is going to have ...
... power of ten relation to the meter.
Right? So that's a good reflection of ...
... the system you are using.
Even the largest number is named.
Do you know the name of the largest number?
No it's er ...
It's exactly the largest number having a name.
Because there is no largest number, right?
So there is this ...
... googol. Right?
And it's just a name invented some time ago. Er ...
That is ten to the power one hundred.
And it's not about so many meters. It's just a name of a number.
But still it's a power of ten.
And you know the Google, name of the company is actually coming from ...
... that name of a number. So that's how they thought of the name.
Er ...
But there are other systems.
Your favorite, isn't it?
And then what's the smaller unit?
Inch.
And how many inches are there in one foot?
Student: [...]. NB: Twelve, all right.
What's the smaller unit?
You never go below inch?
There is nothing smaller than inch?
Is it centi-inch or milli-inch?
Is there anything greater than foot?
NB: Or everything in your life is between inch and a foot? Student: Yard. NB: Yard.
Yard. How many feet are there in one yard?
Student: Three. NB: Three, OK. It's times three.
And anything greater than yard?
Mile?
And how many yards are there in a mile?
Student: Five thousand two hundred eighty divided by three.
What?
Student: [...].
So five thousand two hundred eighty ... divided by three? Student: Yeah.
Is that a very simple explanation?
But if you explain something in preschool ...
... you wouldn't go in that complicated system of multiplying by hundred, right?
You'll definitely explain five thousand two hundred eighty divided by three.
Is it divisible by three by the way?
[...] it's divisible.
You wanted to hide it from me.
Which is much simpler, right? One thousand seven hundred sixty feet in one ...
Well yard in one mile, right?
And that's how many feet are there in one mile.
OK. All right.
So can you use ...
... the number system ...
... to reflect that?
Because that system has perfect reflection in numeric decimal presentation.
You write a number, you write just digits, right?
And you see the digits of how many kilometers you have there.
You see digit of how many extra meters you have there.
You have digits of how many centimeters, millimeters and so on.
Right? One presentation of numbers shows you everything immediately.
Which base should i go for?
Base three or base twelve?
And I had amazing story a few years ago when I had to replace ...
... carpet in one of my rooms with hardwood.
So the story was I measured my rectangular room.
And I got measurements.
I don't remember exact numbers but eight feet ...
... three inch by ...
... well ten feet eight inch.
So I took those two numbers and I went to the store.
And how do you think they sell hardwood?
What do they need to sell me hardwood?
They need square foot, right? Square footage.
So they ask me 'Well, what the square footage do you need?'
I said 'I'm sorry, I don't know.'
This is how wide the room is, this is how long the room is.
But I don't know square footage.
And he just looked at me 'Well.'
You know you have to multiply these numbers.
And I said 'Well, can you do it for me, please?'
And sure he did.
And do you know what he did?
Because I didn't do it just out of curiosity to see what he would do.
And he took his calculator.
And he punched ...
... eight point three times ten point eight.
Gave me the number.
That's how much you'll have to buy.
So ...
Here is my question to you.
Is he in danger?
Student: Yes.
NB: In danger of what? Student: [...].
Is he selling me more or less?
Because if he selling me less he is in danger of me complaining later.
But he is selling me more, right?
And how much more on average?
Well that would require some computations but I came up with ...
... plus two percent.
On average. Because if I come with eight by ten he will sell me exact number, right?
But if people come with different decimals ...
... then on average right thing he will sell ten percent more stuff.
Good business, you know.
Well of course that's not the end of the story about the business.
Because then you come back those people putting the floors.
And I tell you to buy more than that.
Because you have to cut pieces at the end, right?
And they tell me to buy ten percent more.
Just for those cuts.
And then what?
Well you probably thought that's the end of the story -- plus twelve percent.
Well they sell hardwood by boxes.
Did you know that?
And I had to buy ...
... five boxes plus a little bit.
And I was scared to buy just five ...
... so that it will not be enough.
So I bought six.
And how much is it to add one box to five?
Isn't it close to twenty percent?
Just because I have to buy a box.
Selling thirty three percent more ...
Well that is not mathematics, right? But this is.
And well ...
I'm not complaining. That was a good floor. I use it but ...
But why would we do ...
... decimal everywhere?
On all the calculators.
And still use feet [...] also know that stuff.
And why is it that ...
... those people in preschool when they learn multiplication table ...
Do you know?
What kind of ... Well you probably know, right?
It's twelve by twelve multiplication table.
So you have to memorize all those multiples.
So why up to twelve?
Why not up to thirteen?
Or just up to ten as in many other countries.
When people use decimal.
Isn't it because of that twelve base?