### Video Transcript

Complete the following model.

The model that’s being talked about
in this question is the part–whole model that we can see underneath. And it’s labeled with some
different measurements of mass. Let’s have a look at what we’ve
got. The whole amount at the top here is
2,435 grams. And the two parts that it’s been
split or partitioned into are interesting. Firstly, we’ve got two
kilograms. This is interesting because it’s a
completely different unit of measurement, isn’t it? We’ve started off with an amount of
grams, and we’ve split it into a number of kilograms and some more grams. And this part is interesting too
because this is the missing number we’re looking for.

Now can you see what makes this
part–whole model tricky? It’s the fact that one of our parts
is in kilograms. If all the parts were in the same
unit of measurement, it’d be fine. We could find out the missing
number quite quickly. So perhaps the first thing we
should do to help ourselves is to convert these two kilograms into grams. And we can use a fact about
kilograms and grams to help us.

There are 1,000 grams in a
kilogram. And so one way to find the number
of grams that there are in two kilograms is to take the number of kilograms that
there are, which is two, and to multiply it by the number of grams there are in one
kilogram, in other words, find out the answer to two multiplied by 1,000. Now there are different ways we
could use to help us multiply by 1,000. But because we’re only multiplying
it by two, it’s quite quick to do in our heads, isn’t it? Two lots of 1,000 are worth
2,000.

So now to make this part–whole
model a little easier to understand, we could cross through our two kilograms. And we could write it in a
different way. We’ve converted our two kilograms
into grams. Two kilograms are worth 2,000
grams. And now we should be able to work
out what our missing answer is. The whole amount is 2,435
grams. One of our parts is worth 2,000
grams. So that’s all our thousands used
up. And we’re just left with our
hundreds, tens, and ones. Our part–whole model started off by
having mixed units of measurement. So the first thing we did was to
convert kilograms into grams. And this helped us see more easily
that 2,435 grams can be split into 2,000 grams and 435 grams. Our missing number is 435.