-
A recipe for banana oat muffins
calls for 3/4 of a cup
-
of old-fashioned oats.
-
You are making 1/2
of the recipe.
-
How much oats should you use?
-
So if the whole recipe requires
3/4 of a cup and
-
you're making half of
the recipe, you want
-
half of 3/4, right?
-
You want half of the number of
old-fashioned oats as the
-
whole recipe.
-
So you want 1/2 of 3/4.
-
So you just multiply 1/2 times
3/4, and this is equal to--
-
you multiply the numerators.
-
1 times 3 is 3.
-
2 times 4 is 8.
-
And we're done!
-
You need 3/8 of a cup of
old-fashioned oats.
-
And let's visualize that a
little bit, just so it makes a
-
little bit more sense.
-
Let me draw what 3/4 looks like,
or essentially how much
-
oats you would need in a normal
situation, or if you're
-
doing the whole recipe.
-
So let me draw.
-
Let's say this represents a
whole cup, and if we put it
-
into fourths-- let me divide
it a little bit better.
-
So if we put it into fourths,
3/4 would represent three of
-
these, so it would represent
one, two, three.
-
It would represent
that many oats.
-
Now, you want half
of this, right?
-
Because you're going to make
half of the recipe.
-
So we can just split
this in half.
-
Let me do this with
a new color.
-
So you would normally use this
orange amount of oats, but
-
we're going to do half the
recipe, so you'd want
-
half as many oats.
-
So you would want
this many oats.
-
Now, let's think about
what that is
-
relative to a whole cup.
-
Well, one way we can do it is
to turn each of these four
-
buckets, or these four pieces,
or these four sections of a
-
cup into eight sections
of a cup.
-
Let's see what happens
when we do that.
-
So we're essentially turning
each piece, each fourth, into
-
two pieces.
-
So let's divide each
of them into two.
-
So this is the first piece.
-
We're going to divide it into
two right there, so now it is
-
two pieces.
-
And then this is the second
piece right here.
-
We divide it into one piece
and then two pieces.
-
This is the third piece, so
we divide it into one, two
-
pieces, and this is the fourth
piece, or the fourth section,
-
and we divide it into
two sections.
-
Now, what is this as a fraction
of the whole?
-
Well, we have eight
pieces now, right?
-
One, two, three, four, five,
six, seven, eight, because we
-
turned each of the four, we
split them again into eight,
-
so we have 8 as the denominator,
and we took half
-
of the 3/4, right?
-
Remember, 3/4 was in orange.
-
Let me make this very
clear because this
-
drawing can get confusing.
-
This was 3/4 right there.
-
So that is 3/4.
-
This area in this purple color
is 1/2 of the 3/4.
-
But let's think about it
in terms of the eights.
-
How many of these sections
of eight is it?
-
Well, you have one section of
eight here, two sections of
-
eight there, three sections
of eight, so it is 3/8.
-
So hopefully that makes some
sense or gives you a more
-
tangible feel for what
it means when
-
you take 1/2 of 3/4.