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Hello and welcome to the 6th
video in the binary series. So
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you more or less now understand
how you can convert a binary
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fraction into a decimal
fractions. But how can we do it
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the other way around? So let's
say I have got a fraction, say 4
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3/4. How can I convert that
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into? A binary fraction. Again,
let's call up on the place value
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table. So the rate explained
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is here. 1248 and
on this side,
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half or quarter.
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And an 8 now what happens in
here when it comes to the whole
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part, the four. I know that I
can build up from using one for
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an nothing else, so I will need
the place value holders.
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And then the radix point now 3/4
by the obvious thinking would be
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always just to put the three in
here. Don't forget that we are
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in the binary, so we can only
use ones and zeros, so we can't
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use a 3, but there are quarters.
So what happens if I take out
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one of those quarters? So if
I've got 3/4 and I take away 1/4
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from it, I am going to left with
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two quarters. But hold on, two
quarters is exactly the same as
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a half. Well, that solves my
problem, because then I can just
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put a digit here. So you might
have spotted this by knowing the
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half and a quarter makes up 3/4.
But this means that four and
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three quarters in decimal is the
same as 100 radix .11.
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In binary. Let's look
at another example.
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3 and 5
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eights. Place values again.
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1. 24 Radix
point half a
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quarter. And an 8.
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Now three is 2 + 1, so I'm going
to use G of this place values
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Radix point here, but when it
comes to 58 again, I'm going to
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be in a little bit of a trouble
to find out what combinations
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going on in here, and therefore
you need to have quite a good
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understanding of manipulating
fractions, adding and
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subtracting them. So if you're
not sure, please do recap days,
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so don't forget that there are
loads of very good online
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resource is that you can recap
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on. Had to add and subtract
fractions, so let's see what
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happens with the five 8 now.
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I can use up one of the AIDS,
but I can use up only one of
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them. So what happens if I take
an 8 away from the 458? So I've
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got 48 left now that Tendai,
because remember any function
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that has got twice as much as
the bottom is at the top, always
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cancers down to half, so the
remainder here is just half.
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That means I need a place for
the zero here, so three and five
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eights in decimal is the same
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as. 11 radix .101.
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In binary.
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Let's look at a slightly
different decimal equivalent, so
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6.25 in decimal. What does it
look like in binary? Now for
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this particular format, it's
good to know the fraction and
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decimal fraction equivalent, so
again, the whole part of the
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table will be 1248, etc. Radix
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point. And then we would have
half a quarter and an 8 here.
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Now.
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This part of the table is the
same, but beyond the radix point
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because I have got the decimal
fractions. Now I would need to
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look at the decimal fractions
here, so half is 0.5, a quarter
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is 0.25. Well, that tells you
something that and then eight is
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0.125. So Luckily this is a
rather simple function to
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convert into binary fraction
because six will be the sum of.
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Four and two. So I need
a placeholder zero for
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the one radix point 1/2.
I'm not using because all
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I'm using is .25 so 6.25
in decimal is the same as
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110 radix .01 in binary.
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Let's look at a
somewhat more complicated
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example, so 5.3125.
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In decimal, what is it equal to
in binary? So again, right down
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the place values. So on the left
hand side of the radix point
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everything is the same as it
always has been.
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And on the right hand
side now I have got
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0.5 zero, .25, zero, .125
and then I have got
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0.0625.
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So let's see which one of these
I need to use to make up my
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#5 is 4 and one and on the
other side of the radix point.
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Now 0.5 is too big because the
0.3125 is less than 0.5, so I'm
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not going to use this. What
happens if I take 0.25 out from
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my decimal fraction part? So if
I've got the 0.3125?
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And I need to take away the 0.25
from it. What do I left with? So
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first of all to carry out this
obstruction I need to fill in
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the zeros 5 -- 0 is five 2 -- 0
is two 1 -- 5. I cannot do so I
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need to borrow.
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11 -- 5 is Six 2 -- 2 is 0.
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.0 -- 0 is zero. Well that
seems rather lucky because the
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0.3125 is just simply the sum of
0.25 and 0.0 sixty five. So
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that's another place value. Hold
up there for.
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5.3125 in decimal is
equivalent to 101 radix
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point. 0101
in binary.
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Now, I hope that seeing these
examples will give you a good
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idea about how to go around
converting binary fractions to
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decimal fractions or decimal
fractions into binary fractions.
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Also, you probably have a little
bit of an idea about how
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difficult or hard inconvenient
converting decimal fractions
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into binary functions can be not
to further add to this
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difficulties, what if I would
need it to convert, such as
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simple fraction? S3 and 4 /. 5
now there are no fifths in the
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binary place value table because
these place values are just
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halves of Hobbs, etc etc. So
there are no 15 that so you can
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sit around there quite a bit of
time to sort of think about what
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I can do. How can I be that
forfeits out of.
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Hop hop squatters, 8 entrance,
etc. Another rather simple
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example that could be also
problematic. Let's say if I
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wanted to convert 5.4 again, .4.
What combinations of 0.5, zero,
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.25, zero point 25, etc would
make up the .4 bit. This sort
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of draws your attention to the
limitations of the binary
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fractions. While not every
single decimal fractions.
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Can be expressed as a finite
binary fraction. We can always
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extend the system to use more an
more digits to express the
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fractions, but unfortunately
this is an inherent property of
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the binary system.
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In the next video I will show
you how we can try to come
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about these problems and see a
different method of converting
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decimal fractions into binary,
which can make things slightly
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easier. But for now I'm going
to leave you with some
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practice questions and you
will find the answers to these
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after the questions.
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So these are the practice
questions.
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And here are the answers.