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### Course: 5th grade > Unit 1

Lesson 4: Decimals in written form# Decimals in written form (thousandths)

Learn how to read and write decimals in different forms, focusing on thousandths. Learn how to decompose a decimal into its parts (20,000, 5/10, and 7/1000) and rewrite it as 20,000 and 507/1000. Created by Sal Khan.

## Want to join the conversation?

- Wait, you can put a comma in a decimal problem?!(47 votes)
- Yes, you can, and should according to most Mathematicians. The standard notation is to use a period as a decimal point, and a comma to separate thousands, millions, billions, etc.

For example:

One thousand should be written as**1,000**

One thousand and twelve-hundredths should be written as**1,000.12**(65 votes)

- Upvote me and I upvote you back(34 votes)
- Who else is getting a vibe that Sal is a robot?(23 votes)
- Me too, he sounds like A.I and laughs really weird(6 votes)

- I am In College technical math and have always used a calculator to do this simple math how do u write 643.30211 in words. know how to write any thing to the left of the decimal in words but when u combine the tenths place with the hundredths place it confuses me(16 votes)
- So when you deal with decimals you always have to remember that the first number to the right of the decimal is a tenth. The one after it is a hundreth. Say that you have the fraction 1/10. In words, you can say that 1/10 is one tenth and in decimal form, it is 0.1. I'm not sure if I answered your question but I hope this helped.(6 votes)

- this confuses me so much(15 votes)
- same, this is crazy😝(7 votes)

- who invented math(8 votes)
- My son is writing decimals in word form and he did not put the "dash" between the number before the decimal and got it counted wrong. For example, for 85.8 he wrote: eighty five and eight tenths and got it counted wrong because it was suppose to be eighty - five and eight tenths. Do you think this should have been counted wrong? I surely don't! If so please explain your reasoning. Thanks you!(12 votes)
- I don't think so, I agree with your reasoning. The dash is not really needed, but it's a way to show that the number is "connected" and one number.(13 votes)

- Do decimal numbers keep going

And at like0:08you added a comma in 20,000 so I’m confused(7 votes)- It depends on what kind of decimal you have. Like if you have 0.5, or one half, it can have infinite zeros after the 5. it would like this: 0.5000000000000000. No matter how many zeros you put after the 0.5 it will not change its value. If you were to add a number in there like this: 0.501000, it is no longer exactly one half. Other numbers like pi have an infinite amount of numbers too. It would look like this: 3.1415926535... (dot dot dots are added to show that the number is a "non terminating decimal")

I hope that helps(9 votes)

- Hi, if you have any questions, just ask.(7 votes)
- Have you tried watching a video again?

That might help. :D(8 votes)

- can we just say for example 700.5 seven hundred point five?(6 votes)
- yes, but if you are in a purely mathematical scenario, you might want to use seven hundred and five tenths(6 votes)

## Video transcript

So I'm going to
write out a number that we're going to think about
how we could say or actually write that number. So I'm just going
to write it out. I'm going to resist the
temptation to actually speak it out because that's
normally how I operate. But I'm not going to
do that right now. So there's several ways
that we can pronounce. So I encourage you to pause
it and try to pronounce it, yourself. You might not even
need to pause it. Well, the first
thing that jumps out, well we've got
20,000 and then some. So maybe we should
write it that way. So we've got 20,000. 20-- actually let
me write it out as numbers first to
really decompose it. So we have 20,000. And then what do we
have on top of that? Well we have 5/10. This is the tenths place. So we can literally
write that as 5/10. 5/10. Then we have 0, 0/100. I'll write that as a
hundredths place just so that we can keep track of it. And then finally,
we have 7/1000, that's the 1000th place. So we could write
that, plus 7/1000. So if we would write
down everything that I just spoke
out loud, we would say that this is 20-- let me
write that a little bit neater. This is 20,000. 20,000 and 5/10. And 5-- let me write out the
word-- and 5/10 and 7/1000. Now, this isn't the
only way to say this. Another way of
thinking about it is to try to merge the 5/10 and the
7/1000 in terms of thousandths. So let's think about this. So we could write this
as-- so once again, we would have our 20,000. But instead of 5/10
and 7/1000, let's write our 5/10 in
terms of thousandths. And the easiest way to do it
is to multiply the numerator and denominator,
both here, by 100. So then we will
have-- so this 5/10 is the same thing
as 500 over 1,000. And the 7/1000 is still 7/1000. And these two
combined are 507/1000. So we could just call
this 20,000 and 507/1000. so let's write that down. So we could just say this
is 20,000 and 507/1000. This is 1/1000, while this right
over here, 1,000, of course, actually represents 1,000. So we got 20 thousands,
that's that right over there, and 507/1000.