Hi everyone in this video
i'm going to show you how to add decimal
numbers
so there are two basic rules of adding
decimals the first rule is to line up
the decimal points of the numbers
and the second rule is to add digits in
the same place value position
so before we go over how to add decimal
numbers
let's talk about place value
so this number is one million three
hundred forty two thousand
three hundred sixty five and one
thousand
four hundred twenty seven ten thousandths
it's such a big number right but don't
worry we only need to
learn a couple place values here
so the first two you want to pay
attention to
is the number before the decimal point and the
number after the decimal point
so the number before the decimal point
is the ones place
and the number after the decimal point
is the tenths place
and the second number before the decimal
point is the tens place and the second
number
after the decimal point is the
hundredths place
and then we also have our hundreds
and thousands place
and our thousandths place and ten
thousandths
place if you are familiar with these
place values that's great because when i
go over how to add the decimal numbers
i'm going to mention them over and over
again
i'm going to go over these four problems
because i think they're different types
of examples
and they will be really helpful for you
to learn how to add decimals
so let's look at the first example 16.35
plus
0.0087 if you were to line up the
numbers like
this just the numbers
instead of lining up the decimal point
you're going to see something like this
and you won't be able to
add the numbers correctly and that's why
we need to follow our first rule
so the first rule says line up the
decimal points so let's do that
so we are going to have 16.35
plus and then you put the zero
underneath the sixth first and then
point zero zero eight
seven notice you have empty space
above eight seven that's
fine you just need to add two more zeros
to line up with the numbers
and then you draw the line and now you
can add the two numbers
so we are going to follow our second
rule that says add the digits in the
same place value position
you want to start from right to left so
that means we need to
start from the ten thousandths place first
and we are going to add
the zero and the seven
and zero plus seven is seven and then we
move on to the thousandths
place and we add the zero and eight and
we get eight
and then we add the five and the zero
on the hundredths place and we get five
next we add three and zero
on the tenths place and we get three
and because we already line up the decimal
point you just need to bring down the
decimal point
and on the ones place we add six and
zero
and we get six and finally on the tens
place
it's one in empty space and then we know
we just need to think of this
as a zero so one plus zero is one
so our answer is 16.3587
so the second example is 16.35
plus 0.087 again you want to line up the
decimal points
first
and again you notice there are empty
spaces
above seven so we're gonna add a zero
here and then there's also empty space
below
one so i'm gonna put a zero here as well
okay so now we're going to follow the
second rule add digits in the same place
value position
so first we're going to add the zero and
seven
in the thousandths place and we get seven
and then at the hundredths place we add
five and eight but notice how when you
add
5 and 8 you get 13 and you can't just copy
13 in the bottom
so what you do is you carry over the one
to the tenths place
and then you write down the three
underneath the 
hundredths place and then
in the tenths place we are going to add
one
three and zero together so we get four
because one plus three
is four and we just continue to copy
down the decimal points
add the six and zero in the ones place we
get six
add the one and zero in the 
tens place and we get one so our final
answer is
sixteen point four three seven
the third problem is 16.35 plus
0.87 so again i already line up the
decimal points and we're going to
add the single digits so let's look at
the
most right place and we see that we need
to add the
five and seven in the hundredths place
so five plus seven is twelve
and we know that we have to carry the
one over
to the to the tenths place so i'm
gonna write one here for now
and i'll copy down the two here and then
we are going to add
one three and eight in the tenths place
so one plus three plus eight
equals four plus eight which is twelve
so that means we have to carry the one
over to the ones place
and then we write down the two in the
tenths place
and i'm again going to copy down the
decimal point
so let's look at the ones place now we
have one six and zero
so one plus six is seven and we also
know that in the tens place we have one
and zero so one plus zero is one so our
final answer for this problem is 17.22
our last problem is 16.35 plus 8.7
notice after i line up the decimal
points we see empty spaces again so
we're going to fill them up
by writing zero so i'm going to write
zero underneath five and zero underneath
one
all right so now let's add the numbers
if we look at the right side we see that
we need to add five and zero on the
hundredths place so we get five
and then on the tenths place we have
three plus seven
so three plus seven equals ten
that means we will write down zero
here
and then carry over the one
to the ones place so copy down the
decimal
point and now we look at ones place we
are going to add
one and six and eight so one plus six
plus eight
equals seven plus eight and that's
fifteen
so we carry over the one to the tens
place
we copy down the five and now we look
at
our most left side which is the tens
place we're going to add
one and one and zero so that's two and
our final answer
is 25.05
