Video Transcript
Daniel has four yellow balloons
and five green balloons. Write an addition equation to
represent the total number of balloons. And write a subtraction
equation to show how many balloons are yellow.
There are two parts to this
question. We’re asked to write an
addition equation, or number sentence, and a subtraction equation. And you know we can look at the
picture of balloons that we’re given, and we can write both an addition and a
subtraction number sentence because the two are linked together. Let’s have a think about
how.
Firstly, we’re told that Daniel
has four yellow balloons and also five green balloons. And of course, we can see these
in the picture. In the first part of our
problem, we’re asked to write an addition number sentence to represent the total
number of balloons. And we know that if we’re
finding the total of something, we need to add to find it.
We could use a ten frame to
help us model this. Let’s put on four yellow
counters and then one, two, three, four, five green counters. There’s only one more space
left in our ten frame, so we can see what the total is. Four and five make a total of
nine, one less than 10. So, let’s write this as an
addition equation. We start off with four. We add another five and we get
a total of nine. Four plus five equals nine. We could also represent this on
a part–whole model, where four and five are the two parts that go together to
make a whole of nine.
Now, these three numbers are
part of a family. They go together. We can also use them to come up
with a subtraction. And in the second part of our
question, we’re told to write a subtraction equation or a number sentence to
show how many balloons are yellow. Well, we’re already told that
there are four yellow balloons. But how can we show this as a
subtraction?
Well, we need to start with the
whole amount, which is nine. And then we need to take away
the part that represents the number of green balloons. We know that there are five
green balloons, so we need to take away five. One, two, three, four,
five. So, how many balloons are we
left with? One, two, three, four. The number sentence that shows
us how many balloons are yellow is nine take away five equals four.
We can use the numbers nine,
four, and five to write both addition and subtraction facts. Four plus five gives us the
total number of balloons, which is nine. And then nine take away five
gives us the number of balloons that are yellow, which is four.
