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## Arithmetic (all content)

### Course: Arithmetic (all content) > Unit 6

Lesson 2: Decimal place value intro# Decimal place value

Introduction to decimal place values and the value of decimal digits. Created by Sal Khan and Monterey Institute for Technology and Education.

## Want to join the conversation?

- What's the highest place value?(147 votes)
- The place values can go on infinitely, although there are not names for them all. Check out this Wikipedia page to see a list of the largest place values:

http://en.wikipedia.org/wiki/Names_of_large_numbers(138 votes)

- Why do we need to use decimals?(109 votes)
- To represent non-whole numbers .(77 votes)

- What is the power of 2?(61 votes)
- The power of two is like saying multiply the number by itself so say 3 is their with a little 2 on the right top side of the 3 you would do the equation 3x3

Hope this helps :-)(71 votes)

- what does come after decillion(46 votes)
- Then comes undecillion, duodecillion, tredecillion, quattuordecillion, quindecillion, sexdecillion, septdecillion, octodecillion, novemdecillion, vinghtcillion ,and centillion and so con.(6 votes)

- Why do we need decimals in math? It just gets in the way of everything and plus, it's just like fractions!(17 votes)
- Well, think about it this way. If a new toy costs $2.99 and you pay with $5, you would not say that the toy is $2 and 99/100. You would say it is $2.99. Decimals make the number the easiest to read.(35 votes)

- So after the decimal point you always start with the tens place?(0 votes)
- Yes, you are quite right. Now, that should help, right Bob?(4 votes)

- What does scientific notation have to do with decimals?(3 votes)
- what does 10to the fith power mean i dont get it?(2 votes)
- 10 is the base and 5 is the exponent. When a question says evaluate 10 to the power of 5, you answer it like so... Basically you times 10 by 10 5 times not 10 times 5, but 10 times 10 times 10 times 10 times 10 the answer would be 100000. so if it says evaluate 10 to the power of 0 the answer is 1 if the question is 10 to the power of 1 the answer is 10. if the question is 10 to the power of 3,it's 10 times 10 times 10. The answer would be 1000.

I hope this was helpful. Don't forget to vote up!:)(2 votes)

- WHAT is the hieghest place valuE??(3 votes)
- The highest place value we have is infinity or ∞. Infinity never ends. Hope this helps!(3 votes)

- What is 10 to the negative 100th power?(3 votes)

## Video transcript

What is the place value
of 3 in 654.213? So let's think about
that a little bit. And to do that, let me rewrite
the number, and I'll write each digit in a different
color. So we have 654 point-- we get
the decimal point-- 213. Now we're pretty familiar, I
think, with what goes on to the left of the decimal point. We know that this right here--
let me do this in a neutral color-- is the hundreds place,
or we could view that as 10 to the second. Let me write that a little
bit bigger down here. So this right here that is the
hundreds place, or you could view that as the 10 to the
second's place, which is the same thing as hundred. This right here is the tens
place, which is the same thing as 10 to the first. This right
here is the ones place, which is the same thing as
10 to the zero. Then if you go one place to
the right of the decimal point, this represents tenths. This represents tenths, or we
could view it as 10 to the negative one. Then, if we go to this magenta,
if we go two places to the right, this represents
hundredths, or 10 to the negative two. And then finally, this 3
represents thousandths. This represents thousandths, or
10 to the negative three. Now, just to answer the question
what is the place value of 3 in 654.213? The place value is
thousandths. That would essentially answer
their question. But to make sure that we really
understand what this means, I'm going to rewrite
this number. We can rewrite this
number as 600. We have 6 hundreds plus 5 tens,
or you could say plus 50 plus 4 ones plus 2/10, plus
1/100, plus 3/1,000. Or we could write this, just
to really make sure we understand what we're talking
about when we mean place value, we can rewrite this
number as 6 times 100, plus 5 times 10, plus 4 times 1-- I
keep doing that in the wrong color-- plus 2 times 1/10, plus
1 times 1/100, and then finally, plus 3 times 1/1,000. So hopefully, when you write it
out like this, it gives you a sense of what it means
we say place value. The 6, three digits to the left
of the decimal, is in the hundreds place, so it represents
6 hundreds. This represents 5 tens because
it's in the tens place. This represents 4 ones. You go to the thousandths
place, this 3 literally represents three
one-thousandths.