Singapore Math: Grade 3a; Unit 1 (part 4) Video Lecture | Mathematics Lesson for Grade 3 (Singapore) - Personal Learning

let's see if we can do a bunch of
problems using everything we have
learned so far about place value so I'm
gonna do I'm gonna make a little table
actually a large table let me write down
I'm gonna use the same color as I've
used before so let's say this is the
thousands thousands thousands and then
so below this I'm gonna put how many
thousand buckets I have or thousand cans
of marbles or whatever you want to
consider then I have the hundreds
hundreds and then I have the tens and
the cut that cut this was tens tens and
then I have the ones I had done in
yellow and what I'm going to do is I'm
going to instead of drawing the the cans
to scale I'm just going to draw a circle
to represent how many of each kind of
can we have and I'll write down kind of
how many marbles are in that can so
let's say on the thousands so let's do
it let's do the first example let's see
in the thousands I have say I have let's
see I wouldn't even try to talk it out
loud there's another one and there's
another one and then on the hundreds
let's say I have and I'm not drawing to
a scale I'm not drawing the hundreds any
smaller although if I did draw him scale
there would be one tenth the size right
let's say that's the hundreds and let's
say I don't know let's say half a bunch
of tens so let's say I know I didn't I
don't know if I could draw them to scale
but I have to draw them a little bit
smaller I'll draw as many I don't have
to do I'm actually getting these
problems from the Singapore math
textbook but I don't have to follow the
exact same numbers as them so let's say
these are my tens and then my ones let's
say and obviously not all of these
circles are created equal
somewhere flatter than others these are
the ones
so my question to you is what number is
this what number does this represent so
remember this is thousands so each of
those circles represent a thousand to
see you understand what we're doing
that's a thousand that's a thousand
that's a thousand so how many thousands
do we have we have three thousand right
you could you could view this as maybe
we're looking at the top of the of the
can that contains the the marbles so
this can't would have a thousand this
one has a thousand and this one has a
thousand so we have three thousand from
the thousands I guess you could call it
from the thousands place how many
hundred do we have well that's a hundred
that's a hundred and how many do we have
we have two of them so we have two
hundred how many tens do we have you
might even be bored now I'm being so
monotonous you have a ten here ten here
ten here ten here ten here how many tens
is that that's five tens what's five
times ten well it's 50 right so the are
tens cans we can contribute 50 marbles
to our overall number and then how many
ones do we have well these aren't cans
these are the individual marbles blown
up so they look really big so each of
these that's one one one one and you can
kind of you know this is the tens place
so each of these each of these circles
is tandy this is the hundreds place
which of these circles is 100 this is
the thousands place so each of these
circles is a thousand and these are this
of course the ones place each of these
circles is one so how many ones do we
have one two three four we have four
ones four ones
so what's our final number it's going to
be three thousand plus 200 plus 50 plus
four so for the ones place we take the
four right we take the four for the ones
place and then what's quit the tens
place how many tens do we have we have
one two three four five we have five
tens so in the tens place and that comes
from the five and fifty right so what's
this number it's 54 54 so it goes in the
hundreds place
well how many hundreds do we have that's
how many right here we have two hundreds
1 2 or 200 200 200
I'm getting I'm I'm hypnotizing myself
let's see so that's two right and that
comes from the number of hundred cans we
have or this two here are the two
hundreds and then how many thousands do
we have well we have three circles or
buckets or cans of a thousand one two
three that's three thousand so another
way to write that that is three thousand
all right so what is how do we say this
number again well we could look at you
know just here we could say well this is
3254 and we could have you know this
expansion notation and we could have
done it the same thing we could said
this is 3254 or three thousands to
hundreds five tens and and four so what
is that that's 3254 so let's do another
one real quick just just cuz well
there's so much fun let me do another
one let me erase this there you go look
how efficient that was okay so let me
let me do another example let me do the
thousands first let me do squares
actually just to just to mix it up so
that's one thousands so I have square
canisters now unless what's my hundreds
let's say I don't have any
I have no cans of hundreds and let's say
my tens I don't know I had let's say I
have four of them and I don't know ones
I don't know let's say I have you can
count them they're not drawn to scale so
what number does this represent well
once again if I just these are each a
thousand all right so this is one
thousand this is one thousand this is a
ten ten ten ten and these are each one
one one one one
so how many thousands we have well we
have two of these canisters of a
thousand so that's two thousand
how many hundreds do we have well we
have zero hundred zero hundred I don't
know to write that any better than just
a zero or zero hundred and one hundred
and how many tens do we have we have one
two three four
well what's four times ten well that's
40 and how many ones do we have one two
three four five well the five times one
is just five
see if 200 plus zero two thousand plus
zero hundreds plus 40 plus five oh I
should have written that last one in
yellow sorry
I want to confuse you so how do we write
that out what happens when we add all of
these together well we could do is do
the exact same way as we did before we
say well you know in the extreme right
we have our ones place so we say how
many ones do we have we have five ones
then we go to the tens place how many
tens do we have we have one two three
four tens so this counts the number of
tens we have how many hundreds do we
have in the hundreds place well I can't
see any we have zero hundred so we have
zero hundred there that's a zero and
then how many thousands do we have or
one two
mm and once again this two is the same
thing as a 2 in 2000 this zero is the
same zero as in zero hundred this four
and forty is the same thing as this four
and this five and five well that's
that's just the five and how do we say
this two thousand there knows there's no
hundred so it's just two thousand forty
five let's do one last one just to like
really really hammer the point home let
me erase this super fast very good all
right so let me draw and I can I'm not
even gonna listen listen I say okay
let's do some thousands first so look at
that that's a weird looking one
then let me do some hundreds you know
let's say that we have I'd say that we
have I don't know if I like it drawn
like this let me make it so it fills in
then let's do the let me do it like that
then let's do the tens yeah I like that
better so that's the tan I don't know
how many of you let me throw a couple in
I don't know if that looks good let's
say we have no ones what number is this
we could do it fast right so how many
ones do we have how many ones listen you
know how many places we have the
thousands place we have but hundreds
place we have the tens place we have the
ones place well how many ones do we have
well I don't see any so we have zero
ones how many tens do we have I see two
tens so we put a two in the tens place
and as we know each of these are ten so
that represents 20 and lo and behold
that's what we have there we have 20
written down and how many hunters do we
have one two that's loaded into the
hundreds place we write the number two
and it represents what it represents 200
right because each of these are 100 so
so far we have 220 and how many
thousands do we have one two three four
so they have for thousands and so
another way of writing well I think you
know how to say this by this point this
is 4220 because you know it's not like
21 or anything cuz we have no ones so
it's 4220 which is the same thing you
could have also written it down you know
four thousand two hundred and twenty
four thousand two hundred and twenty I
think I'm writing it as many different
ways as I can so it really hits the
point home so let me do it let me do one
last one just cuz you know we've we've
done it where we had no hundreds we've
done it where we had no ones so let me
do another example where we might have
no something else let's say we have
I don't know let's say we have one
canister of a thousands I don't know
let's say we have three hundreds so we
have no tens I know let's store a couple
in here more than a couple these are all
even though they're different sizes
these are all represent one so what is
this number
well how many ones do we have what goes
in the ones place we have one two three
four five six ones so one I'm using the
wrong tool we have one one so that's the
ones place so now we're in the tens
place how many tens do we have I don't
see any we have zero zero tens how many
hundreds one two three hundreds and how
many thousands well we have 1,000 so how
do we how do we say this number well we
have 1,000 plus one two three hundreds
plus zero ten so we can ignore that and
then we have 6 1 so plus six so it's
1,000 oh sorry this is three hundred not
three thousand ignore that three hundred
so it's 1306 there's no tents oh I don't
know why I wrote us one here there's
this 6 1 2 3 4 5 6 this is 6 I almost
have been thinking ones place and I
wrote a 1 there so even the best of us
can make careless mistakes so as I said
and that's why I did a different way so
we I caught myself what is this number
it is 1306 or 1306 or 1,000 plus 300
plus 6
hopefully you found that useful I'll see
in the next video