the

Math - Decimals: tenths & hundredths places

okay so yesterday we talked about

decimals we did a little bit with

fractions and then we started talking

about decimals and with decimals we

talked about how we're going to say that

this is just one thing okay it's not a

hundred things like we've known of it

before but it's just one thing and in

this one thing how many parts did we say

there were a raise your hand please

how many parts did we say there were

there's 100 parts of this one thing so

this is like we've got a pizza we split

it up 100 ways it's like we have a

dollar bill and we make it 100 pennies

okay so that's what we talked about with

decimals now when we talk about place

value we talk about place value I want

you to tell me if I just write this here

what place is this yes this is the ones

place so anything in this place is going

to be equal to that number so I'm going

to put a a - okay what place is this yes

the tens place okay so anything in this

box is going to be equal to that number

times 10 all right so I'll put a 3 here

what this is a 3 in this place mean what

is the 3 mean yes means 30 good and how

about this what place is this

what place is this yes it's the Andres

good and whatever number is here means

this number times 100 okay so what does

this number really mean what does this

number really mean yes 400 okay so if we

read this number how do we read it yes

432

okay now I've said I've told you before

there's a hidden decimal in every number

even if it's not written I want somebody

to tell me where I'm going to find the

decimal in this number am I going to

find it before the hundreds after the

hundreds after the tens after the ones

or somewhere else

yes okay so if I put the decimal point

here then I would have point four three

two okay so that means it's less than

one of these all right that was good

thinking but thinking because we've

worked with some numbers that look like

that yes after the ones okay exactly

the hidden decimal always goes after the

ones so this number is the exact same as

this number the exact same look at the

here not my hand exact same okay and I

could put zeros after that remember

we've talked we talked about that

yesterday how many zeros can I put after

that how many zeros could I put yes many

as I convinced I want is that going to

be equal to this still it is it's the

exact same we're going to start talking

about two new place values today that we

haven't talked about before but you've

seen before and we've worked with a

little bit there on the right hand side

of the decimal okay so all the place

values we've talked about and then on

the left hand side of the decimal well

we need to start talking about a couple

of place values on the right hand side

of the decimal

okay so this place value here I'm going

to tell you actually

this is a place that it represents and I

want to know if does anybody have any

thoughts about what this place value

might be but it might be yes we talk

about white when you run out of like

space on your paper you go after the

decimal I'm not sure let's get back to

that question okay so this moist value

here is actually called tenths place

okay now look very carefully how I spell

this ten so you know I have a th in

there

this th is so important because it's the

difference between ten of these or one

of these just a piece okay if this is my

ones this is ten of those right this is

a tenth of those which is bigger tents

or tens take a look which is bigger give

me a thumbs up if you think tenths is

bigger give me a thumbs up if you think

tens is bigger you are absolutely right

tens is much bigger intense because

tents is only a tiny piece of one it's

actually tents is 1/10 that's where we

get that you've probably heard of 1/10

before ok and if I have more than one in

this place it would be that number 2/10

3/10 4/10 5/10 ok and you can see what

that looks like right here i if you want

to compare it how many tenths do I have

here if this if I use this

representation how many tenths do I have

here yes

3 3 tents ok so I could write that there

if I want and then this would mean three

of those tents ok now if this place is

tens and this place is tents

does anybody have any idea what this

place might be ok I'll tell you it kind

of looks like a mirror set the th it

kind of looks like a mirror does anyone

have any thoughts about what this place

might be yes ah a hundred hundreds

good very good ok so I'm gonna write it

just like I would write limerence except

I'm gonna do hunch

drip hundreds place ok so it goes all

the way the same except there's the th

in there ok now when I write this it's

going to mean hmm

one of these this is this right here is

one 101-100 so what do you think is

going to be bigger 100 of these or 1/100

imagine one want to imagine a hundred of

these and then imagine 1/100 which is

bigger do you think yes

hundreds much bigger hundreds is tiny

okay so I'm looking if you see a pattern

here if you see a pattern if if I have

so this is 1 and I have 10 of these and

I have a hundred of these ok this is my

tenth I have ten of these I have 10

little ones right 1/10 1/100 are you

noticing a pattern what's happening to

these numbers as I go to the right yes

they're getting tinier what happens to

these numbers as I go to the left they

get higher yeah so sometimes they'll try

to trick you on your test or some

problem will ask you which number is

bigger you might have sixty five digits

over here and just one big digit over

here well - and it's gonna say which is

bigger some kids get tricked because

they think more digits means a higher

number that's not true if these digits

are on the right side of the decimal

point okay doesn't matter how many we

have if you've got digits over here it's

not bigger than this no matter how many

of them there are is everyone looking up

here so that you can see all the digits

over here that you can fit are not

bigger than this okay it might seem

strange to you because we're used to

seeing big numbers mean big big things

mm-hmm okay

and when you do this if we say I've got

five of these I'm going to have five

hundredths okay so I'm going to put five

hundredths here and that interaction is

going to be five over 100 you can think

about it that way so if I was talking

about this in terms of dollars and cents

how many dollars and cents would I have

raise your hands

yes and 35 cents so you can think of

anything on the other side of this

decimal in these first two places in the

tenths and hundredths place and cents

like money okay you can think of you've

heard of dollars and cents notation okay

so when you go to work in your workbook

today on page 117 you will see you will

see a thing that looks like this okay

and it will also want you to tell how

many hundredths there are how many

tenths how many uh and how many

hundredths go with that it's going to

want you to break it up so the example

is thirteen hundreds hundred if I have

thirteen hundred how many tenths is that

thirteen hundreds is how many tenths and

how many hundreds that's what it's gonna

ask you to do okay how many tenths and

how many hundredths is that in 1300s how

many tenths in here do you see how many

tenths yes one tenth okay and so if we

have one tenth how many hundredths are

there how many hundredths are there yes

we have one tenth how many hundredths

how many hundredths you're absolutely

right

good a nice show of fingers three

excellent so 110 and three hundredths

you're actually going to get to pick

your own number of hundreds okay you can

pick any number of hundredths you want

all right from one to ninety nine

hundredths okay you have five or six

different examples that you're going to

try okay and if you have questions I

will come around and answer them right

I'd like you to get to work