Video Transcript
Subtracting Numbers up to 10
In this video, we’re going to learn
how to find the answer to a subtraction question when we’re subtracting with numbers
up to 10.
Let’s start with this short
line. Or is it a rectangle? Well, this is much more than just a
short line or a rectangle. If we write a number either side of
it, we can see that it’s actually a symbol. It represents something. And you remember what this line
represents in math. It’s the subtraction symbol, and it
shows that we need to subtract or take away. And our numbers tell us what to
take away from what. Our first number is eight. This shows the number that we’re
starting with, the number that we’re taking away from.
To help us, let’s show eight using
a line of cubes. One, two, three, four, five, six,
seven, eight. So, we have eight to begin
with. Now we have this symbol that we
talked about. It tells us that we need to
subtract or take away a number of these cubes. Although we started with eight,
we’re going to end up with less than eight because we’re going to take some of these
cubes away. How many do we take away? Well, that’s what our second number
tells us. We need to take away or subtract
five.
How could we show this using our
eight cubes? What if we pick up and actually
take away five of the cubes? One, two, three, four, five. We started with eight cubes, and we
took away or subtracted five cubes. How many cubes are left? One, two, three. Eight take away five equals
three. And we know this because five and
three are two numbers that go together to make eight. Another way we could model a
subtraction might be to use a 10 frame and counters. Let’s use a 10 frame to help find
the answer to seven subtract two.
Remember that the first number in a
subtraction is the number that we’re starting with. The number that we’re going to take
away from. Our first number here is seven, so
we’re going to need to start with seven. Let’s put seven counters on our 10
frame. Five across the top, six,
seven. So, we start with seven. And remember, this symbol here
tells us we need to take away a number. We’re going to have to take away
some of our seven counters. And our second number tells us how
many to take away.
We need to start with seven and
then take away two. Let’s cross them out as we take
them away. One, two. We’re left with just this top row
of counters here. And we know that a row of counters
on a 10 frame is worth five. Seven take away two equals
five. And we know this because five and
two more make seven.
Do you think you can try answering
some questions now where we have to take away numbers up to 10? Let’s have a go, and we’ll see how
good you are at subtraction.
Subtract to find the missing
number. Nine take away four equals
what.
In this question, we need to
subtract or take away to find the answer. Now there are three clues that show
us we need to do this. Can you spot them? The first one is in this sentence;
in fact, it’s the first word “subtract.” Our second clue is in the
picture. What can you see that shows us we
need to take away? Well, our picture shows some
counters, but some of the counters have been crossed out. This shows us that our number is
getting less. We’ve taken away these
counters. And our final clue is in this
number sentence here. Can you spot what tells us it’s a
subtraction?
This little line here is the
subtraction symbol. And so, we read this calculation as
nine take away four. So, what is nine take away
four? Well, we’re given this picture here
to help us. Now the number nine in our
subtraction tells us the number that we need to start with. Can you see how many counters we
started with in the picture? There are one, two, three, four,
five, six, seven, eight, nine counters.
But something’s happened to some of
our counters; they’ve been crossed out. We need to take them away from our
nine counters and forget about them. Let’s count how many counters we’ve
taken away. One, two, three, four. This is where the number four comes
from in our number sentence. We started with nine counters and
we took away or subtracted four counters. So, what’s the answer? How many counters do we have
left? There are one, two, three, four,
five counters left over. We started with nine and we took
away four. We’re left with five. Nine subtract four equals five.
Subtract to find the missing
number. Seven take away four equals
what.
When we start with a number and
subtract or take away from it, that number gets less, it gets smaller. And in this question, we’re making
a number get smaller too. We need to find the answer to seven
take away four. Can you see why we describe this
calculation like this? Let’s point to each different part
as we say it. Seven take away four. Now we’ve read the number
sentence. But what does each part of it
actually mean? Seven is the number we start
with. Before we do any taking away at
all, we have seven. And can you see in the picture
there are seven counters ready for us to start?
We know that there are always five
counters on the top row of a 10 frame. So that’s five, six, seven. Now this symbol here tells us that
we need to take away or subtract. What does it mean when we take away
or subtract from a number? Well, we remove part of the number;
we take it away. And so, the number that we started
with becomes less. Well, we have seven counters here
on our 10 frame. By the end, we’re going to have
less than seven. We’re going to take some of them
away. How many do we need to take
away? Our second number tells us
this. We need to take away four.
Now, how could we show on our 10
frame that we’ve taken away four? If we had a real 10 frame in front
of us, perhaps we could pick up four counters one by one and put them in our
pockets. But this is a picture of a 10
frame. Perhaps, we could cross them
out. Remember, we need to take away
four. One, two, three, four. Our 10 frame is now four less than
it was. There were seven counters on it,
but now there are one, two, three left. We know that three and four more
make seven altogether. And so, if we start with seven and
we take away four, we’re going to be left with three. Seven take away four equals
three.
Take away counters to find the
missing number. Six subtract three equals what.
In this question, we need to take
away or subtract to find the answer. And this symbol in our number
sentence shows us this. It’s the subtraction symbol. It shows us that we need to find
three less than six. In other words, we need to start
with six and take away three from it. Now we could try to find the answer
in our heads or maybe draw a little sketch to help. But in this question, we’re told to
take away counters to find the missing number. And we’re given this line of
counters. Now without counting the counters,
do you think you know how many there are?
We said that the first number in
our subtraction is six. This is the number we begin
with. So do you think it might make sense
if we had six counters? Let’s see. One, two, three, four, five,
six. So, we’ve got our six counters to
begin with, and now we need to take away three of them. Now, before we do this on the
screen, let’s really put your brains at work. Without drawing anything or writing
anything, I want you to look at these six counters and I want you to imagine taking
away three of them. Can you see how many there are
going to be left? See if you can predict what the
answer is going to be.
With each counter that we take
away, we could cross them through. So, we need to take away one, two,
three. And this leaves us with one, two,
three. Six take away three equal
three. We know that if we add three and
another three together, we get six. So just like in this subtraction,
if we start with six and then we take away three, we’ll be left with three. We’ve taken away counters to help
find the missing number. Six subtract three equals
three.
Nine subtract seven equals
what.
There are no words in this
question, just some numbers and symbols. Let’s go through them one by one to
try and work out what we’re being asked. First, we have the number nine. This is the number we’re starting
with. Whatever we’re going to have to do
in this calculation, we’re going to need to do it to the number nine. So, why don’t we model the number
nine? Let’s make a line of nine. Here are nine cubes. Now, what are we going to do with
our nine cubes?
This symbol here tells us we need
to take something away from them. So, although we have started with
the number nine, our answer is going to be less than nine. We need to subtract or take away
something from our nine. And how many do we need to take
away? We need to subtract seven. Do you know how many cubes are
going to be left? Let’s subtract seven of our
cubes. One, two, three, four, five, six,
seven. So, what do you think our missing
number is going to be? It’s the number that we have left
if we take away seven from nine. And we can see that there are two
left because seven and two make nine altogether. And so, we know nine subtract seven
equals two.
So, what have we learned in this
video? We have learned how to find the
answer to subtractions using numbers that are less than 10.
