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Studying for a test? Prepare with this lesson on Parts and wholes.

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# Fractions cut and copy 2 exercise example

Video transcript

The starting block
below is 2 units long. Use the tools to the right
to convert the starting block into both of the
goal blocks, that are 5/8 units long, and
1 and 3/4 units long. You can see your progress
as the current block. So what are they
telling us to do? So this is the starting
block, right over here. They're telling us
this is 2 units long. So a unit must be about
this long, right here. About half of this
starting block. And we have these
tools on the right. And my first goal block,
right over here in blue, they say that that's 5/8. And that makes sense, because
if this is about a whole, then that looks like about 5/8. This right over here
would be about 8/8. So this looks about 5/8. And then they tell us
that this other one that's below my screen right
over here is 1 and 3/4. So they tell us that this
is 1 and 3/4 units long. 1 and 3/4 is also the
same thing as 7/4. So I somehow need to-- let's
see, what are my tools? What are the tools
available to me? Well I can cut my starting
block into a certain number of pieces. And then I'm going to copy
that starting block over here for block 1, and
I'm going to try to match it to this goal block. And then I'm also going
to copy it for block 2, to match that second goal block. So I'm going to try to
get something that's 5/8, and I'm also going to try to
get something that's 1 and 3/4. Now 3/4 is the
same thing as 6/8. And the reason why I care
about eighths is eighths is a smaller unit. So if I can convert the
starting block into eighths, then I can copy it enough
times to get exactly to 5/8, and exactly
to 1 and 3/4, which is the same thing as-- 3/4
is the exact same thing as 6/8. So let's get our starting
block into eighths. So if we're starting
with 2 wholes, if we're starting with 2 units
long-- So if I cut it once, now this is a whole unit. Now if I cut a whole,
now if I cut it twice, so now if I cut 4 times, so
I've cut my original block into 4 times. So now this right over
here is half a unit. And actually, if I want
to convert it into eighths I need to cut it 16 times. So let me do that. 15, 16. So I cut 2 units
into 16 equal pieces. Or I guess this is 1/16 of 2, so
that is going to be an eighth. And now I just have
to multiply this the appropriate number of times. This right over here is 5/8. This is 1/8. So let me copy
this, 1, 2, 3, 4, 5. So that is 5/8. And then here, I
need to do 1 and 3/4. Remember, 1 and 3/4 is
the same thing as 7/4. It's 4/4 plus 3/4, which is 7/4. 7/4 is the same thing as 14/8. So this right over
here is 1/8, I just need to make 14 of these. 2, 3, 4, 5, 6, 7, 8. Actually, let me show
you what I'm doing. 9, 10, 11, 12, 13, 14. And there we go. That's exactly the same
length as goal block 2. This is 14/8. 14/8 is the exact
same length as this. 14/8 is the same
thing as 7/4, which is the same thing as 1 and 3/4. This is 5/8, which is
the same thing as 5/8. So let's check our answer. And we got it right.