Addition 3

Practice carrying digits to add multiple digit numbers

What I want to do in this video
is one, just do a bunch of

addition examples so that we
really get some good practice

and we really get warmed
up with addition.

And what I even more want to
show you is that we now have

all the tools we need to really
tackle any addition problem.

So let's just get warmed up
with some one-digit addition

problems, but these are the
ones that always give me a

little bit of a headache.

Let's start with a really,
relatively straightforward one.

I want to say two plus four.

Well, we know what that is.

I don't think we need to draw
the number line at this

point, but you can if you
need to remember this.

Two plus four is six.

Not too bad.

What about nine plus three?

We saw that in the last video.

Nine plus one is ten.

Plus another one is eleven.

Plus three is twelve.

Nine plus three is twelve.

And it's probably
not a bad idea.

It's good to visualize what's
happening here, but it's also

not a bad idea to be able
to do these very fast.

To be able to memorize, at
least what the one-digit

addition problems end up being.

Let's do a couple
of harder ones.

Six plus seven.

This one I used to find
difficult to remember.

But six plus seven is thirteen.

Draw out the number lines
and the lemons and limes

if you don't believe me.

Six plus seven is thirteen.

Eight plus six or six plus eight
is going to be fourteen.

And that's the same
thing as seven plus seven -- is

also going to be fourteen.

And if you think about
it, we got the same

number here as there.

And it makes sense, right?

Because we took one away from
eight, but we had one more than six.

So it's like you just shifted
the one from the eight to the six.

That's why we got
the same answer.

If that confused
you, ignore it.

Let's just do a couple
of more of these.

So eight plus eight is sixteen.

These are things that hopefully
you'll be able to do super fast

in the not too far off future.

Five plus six.

Well, that's eleven.

Let me just do a couple
of more really fast.

So let's say seven plus nine
is going to be sxiteen.

You might want to draw
the number line if

you don't believe me.

And that's going to be the same
thing as eight plus eight, is also sixteen.

And then nine plus nine is eighteen.

And then nine plus eight is seventeen.

And that's just a
little bit of warm up.

We didn't do all of the
possible combinations of

one-digit numbers, but these
are some of the ones that

give people a little
bit more headache.

So now that we've done that
let's tackle some larger digit

numbers that we started
doing in the previous video.

Maybe I'll leave
that there for now.

So let's do a couple of them.

Let's do twenty-two plus three.

So we go to the ones place.

Two plus three is five.

We didn't have to
carry anything.

And then in the tens place we
just have this two sitting here.

So we just take that two.

Two plus nothing -- it's two tens.

It's two dimes.

So then we put that down there.

So we get twenty-five.

Two dimes and five pennies, or twenty-five cents
depending -- a lot of people,

money makes it easier to
understand things or maybe

to be motivated to
understand things.

All right, let's
do another one.

What is thirty-eight plus seventeen?

So we look at just
the ones place.

What is eight plus seven?

We haven't done that one
yet; I'll do it up here.

Eight plus seven is equal to--
it's going to be one

more than eight plus six.

Eight plus six is fourteen, then eight
plus seven is going to be

one more than that.

So it's going to
be equal to fifteen.

So in this problem we
write the five here.

Let me write this in
a different color.

So the five in the fifteen we'd
write right down there

in the ones place.

And we would carry the one
because that's one dime.

That's one ten.

You know, this fifteen,
this is ten plus five.

So this one really means
one ten or one dime.

So we put that one up there
in the tens place.

We have one plus three is four.

Plus one is five.

So you get fifty-five.

One plus three plus one is this five.

Thirty-eight plus seventeen is fifty-five.

Or five tens and five ones.

That's the same thing as fifty-five.

Let's do a couple
more problems.

I think you'll see that we
have the tools to tackle

anything, any problem.

Let's say we have forty-seven.

Let me switch colors just
so it stays interesting.

Forty-seven plus nine.

We just look at the ones place.

Seven plus nine.

We know what that is already.

We did that problem already.

Seven plus nine is sixteen.

So you write the six in the ones
place and carry the one.

And now it's in the tens place.

Because this is one
ten right there.

So one dime plus four
dimes is five dimes.

So it's five dimes and six pennies.

It's fifty-six.

Let's do slightly
harder problems.

Let me scroll down a little
bit so we have some

space to work with.

We always need that.

All right, let's do
something hard.

Ninety-nine plus eighty-eight.

That's a hard one.

And you just have to look at
the parts of the problem and

you'll see how it'll
all work out.

You say, what's nine plus eight?

We did that up here.

Nine plus eight we know already is seventeen.

That's a good one to remember.

Nine plus eight is seventeen, but it's
always good to be able

to visualize it as well.

So nine plus eight is seventeen.

Carry the one.

And then we have
one plus nine is ten.

Ten plus eight is eighteen.

Now this is interesting.

We want to write eighteen down.

So we write our eight down there.

We have one plus nine plus eight.

One plus nine plus eight is equal to eighteen.

We wrote the eight down there and
we say, let's carry the one.

We carry the one, but we carry
it into the hundreds place.

This was the ones place,
the tens place, now we're

in the hundreds place.

But there's nothing else
in the hundreds place.

So it just drops straight down.

So you could almost just
write the eighteen just like that.

So ninety-nine plus eighty-eight is one hundred and eighty-seven.

Let's keep doing some examples.

You could see, it's
all the same pattern.

We could add two ten-digit
numbers to each other as

long as we're just careful
about carrying our digits.

So let's do seven hundred -- let
me switch colors.

Well do some
three-digit numbers.

Let's do a four-digit number.

Let's not mess around.

Let's do a four-digit number.

So let's do four thousand, three hundred and sixty-eight plus five hundred and seventy two.

Let's see what happens here.

I'll write it down here.

Eight plus two.

We know that that
is equal to ten.

You can do the number
line if you need to.

Eight plus two is equal to ten.

Put the zero in the ones
place, carry the one.

Now we're in the tens place.

This is really one ten.

This is six tens.

This is seven tens.

Or you could think of
them as dimes if we're

thinking about change.

So one dime plus six
dimes is seven dimes.

Seven dimes plus seven dimes is fourteen.

Let me write it like this.

We could write one plus six plus seven
is equal to -- one plus six is seven.

Seven plus seven is fourteen.

So this right here is
going to be equal to fourteen.

Carry the one.

Now we have-- let me do
it in another color.

I'll do it in pink.

We have one plus three.

We're in the
hundreds place now.

Plus five.

One plus three plus five.

Well, one plus three is four.

Plus five is nine.

Four plus five is nine, so this is
going to be equal to nine.

Nothing to carry.

We only had something
in our ones place.

Nine is just nine pennies.

It's no dimes.

It's just nine pennies.

And then we go to the
thousands place.

Nothing to add to the
thousands place.

So you just take this four thousand --
you see a four here, but since

it's in the fourth digit to
the left, this means four thousand.

So this four thousand right here, we
don't have any other thousands

to add it to, so we just
bring it straight down.

So you bring the four down there.

So four thousand, three hundred and sixty-eight plus five hundred and seventy-two is four thousand --
we'll put a comma there

to make it easy to read --

four thousand, nine hundred and forty.