Video Transcript
Subtracting from Eight and Nine
In this video, we will learn how to
use pictures and subtraction sentences to find all the ways to take away from the
numbers eight and nine. Here’s a picture of eight cars in a
ten frame. If we take one car away, there will
be seven cars left. We could write this as a
subtraction sentence. Eight subtract one equals
seven. Eight subtract two equals six. Eight subtract three equals
five. Eight take away four equals
four. Eight take away five equals
three. Eight subtract six equals two. Eight subtract seven equals
one. And if we subtract all eight cars,
there will be no cars left.
Let’s look closely at the
subtraction sentences. What do you notice? Did you notice that each
subtraction sentence begins with the number eight? This is because this is the number
of cars we had to start with. This column shows the number of
cars we took away each time. What do you notice about these
numbers? One, two, three, four, five, six,
seven, eight. These numbers increase by one each
time. We’re adding one each time. What do you notice about the
numbers in the third column? These are the number of cars that
are left. Seven, six, five, four, three, two,
one, zero. These numbers are decreasing by one
each time; we’re taking one away each time.
We’re going to use these patterns
in subtraction sentences and pictures to help us find all the ways to take away from
the numbers eight and nine.
Ethan is subtracting from
eight. Write the missing sentence. Eight take away one equals
seven. Eight take away two equals
six. Eight take away three equals
five. Eight take away four equals
four. What? Eight take away six equals
two. Eight take away seven equals
one.
In this question, we need to
find the missing subtraction sentence. We can use the pictures or the
number sentences to help us find the answer. We know that the number at the
start of our number sentence is the number eight because all of the other
subtraction sentences start with the number eight. And if we look at all of the
pictures of ten frames, we can see that they all contain eight counters. We can write the subtract
symbol after the number eight because all of these number sentences are
subtraction sentences. But we don’t know how many to
subtract. Let’s use the number sentences
to help us.
Let’s look closely at what
happens to the number that we’re subtracting each time. One, two, three, four,
five. We can use the picture to check
if we are taking away five. One, two, three, four,
five. Now, what we need to do is work
out how many counters are left. What is eight subtract
five? Let’s use the number sentences
again to help. Seven, six, five, four,
three. Seven, six, five, four,
three. Let’s check the picture to see
if there are three counters left. One, two, three. Yes, there are. Eight take away five equals
three. The missing subtraction
sentence is eight take away five equals three. We use the pictures and the
subtraction sentences to help us find the answer.
Victoria is subtracting from
nine. Write the missing sentence. Nine take away one equals
eight. Nine take away two equals
seven. Nine take away three equals
six. What? Nine take away five equals
four. Nine take away six equals
three. Nine take away seven equals
two. And nine take away eight equals
one.
In this question, we need to
write the subtraction sentence which matches this picture. We know our subtraction
sentence begins with the number nine because all of the subtraction sentences
begin with the number nine because there are nine counters in the ten frame to
start with. We also know that this is a
subtraction sentence, but we don’t know how many we need to subtract. Let’s use the picture to help
us. We’re subtracting one, two,
three, four.
We can also use the subtraction
sentences to help. The number that we subtract
each time increases by one. One, two, three, four. Now, all we need to do to
complete our number sentence is write the number of counters that are left. We could use the subtraction
sentences to help again. We’re taking away one more each
time. The numbers are going down by
one each time. Eight, seven, six, five. Nine subtract four equals
five. We found the missing
sentence. We use the pictures and the
subtraction sentences to help.
What have we learned in this
video? We’ve learned how to use pictures
and subtraction sentences to find ways to take away from the numbers eight and
nine.
