1
00:00:00,000 --> 00:00:00,500


2
00:00:00,500 --> 00:00:03,220
We're asked to subtract and
simplify the answer, and we

3
00:00:03,220 --> 00:00:06,170
have 8/18 minus 5/18.

4
00:00:06,170 --> 00:00:08,500
So subtracting fractions
is very

5
00:00:08,500 --> 00:00:09,920
similar to adding fractions.

6
00:00:09,920 --> 00:00:12,620
If we have the same denominator,
the denominator

7
00:00:12,620 --> 00:00:14,460
in the difference is going
to be the same as the

8
00:00:14,460 --> 00:00:16,379
denominators in the two
numbers that we're

9
00:00:16,379 --> 00:00:18,700
subtracting, so it's
going to be 18.

10
00:00:18,700 --> 00:00:20,900
And our numerator is going to be
the difference between the

11
00:00:20,900 --> 00:00:21,470
numerators.

12
00:00:21,470 --> 00:00:26,750
So in this case, it is 8 minus
5, and this will be equal to 3

13
00:00:26,750 --> 00:00:30,900
over 18, which is the answer,
but it's not completely

14
00:00:30,900 --> 00:00:35,250
simplified, because both 3 and
18 are divisible by 3.

15
00:00:35,250 --> 00:00:37,450
So let's divide them
both by 3.

16
00:00:37,450 --> 00:00:42,540
So you divide 3 by 3, you divide
18 by 3, and you get 3

17
00:00:42,540 --> 00:00:44,390
divided by 3 is 1.

18
00:00:44,390 --> 00:00:49,000
18 divided by 3 is 6,
so you get 1/6.

19
00:00:49,000 --> 00:00:53,280
And just to see this visually,
let me draw 18 parts.

20
00:00:53,280 --> 00:00:56,030
Let me draw 18 parts here.

21
00:00:56,030 --> 00:00:58,395
So it might be a little bit
of a messy drawing.

22
00:00:58,395 --> 00:01:00,070
I'll try the best I can.

23
00:01:00,070 --> 00:01:02,810
So let me draw six in
this direction.

24
00:01:02,810 --> 00:01:06,900
So that is three right there.

25
00:01:06,900 --> 00:01:09,730
We have another three,
so that's six parts.

26
00:01:09,730 --> 00:01:12,990
And then let me split this
into three columns.

27
00:01:12,990 --> 00:01:13,690
So there we go.

28
00:01:13,690 --> 00:01:15,390
We have 18 parts.

29
00:01:15,390 --> 00:01:24,050
Now 8/18 is equal to one,
two, three, four,

30
00:01:24,050 --> 00:01:27,330
five, six, seven, eight.

31
00:01:27,330 --> 00:01:28,990
That's 8/18.

32
00:01:28,990 --> 00:01:33,370
And now we want to subtract five
of the eighteenths, so we

33
00:01:33,370 --> 00:01:38,210
subtract one, two, three,
four, five.

34
00:01:38,210 --> 00:01:39,525
Now, what do we have
left over?

35
00:01:39,525 --> 00:01:43,150
Well, we have three of the
eighteenths left over, so you

36
00:01:43,150 --> 00:01:44,960
have that right there.

37
00:01:44,960 --> 00:01:48,340
You have three of the
eighteenths left over.

38
00:01:48,340 --> 00:01:52,340
Now, if you turn three of the
eighteenths into one piece,

39
00:01:52,340 --> 00:01:54,500
how many of those bigger
pieces do you have?

40
00:01:54,500 --> 00:01:56,450
This is one of those
big pieces.

41
00:01:56,450 --> 00:01:57,640
Now, where are the other ones?

42
00:01:57,640 --> 00:02:00,820
Well, this is another big
piece right here.

43
00:02:00,820 --> 00:02:03,720
This is another big piece
right here, another one,

44
00:02:03,720 --> 00:02:04,970
another one, and another one.

45
00:02:04,970 --> 00:02:08,110
If you had 18 pieces and you
merged three of the pieces

46
00:02:08,110 --> 00:02:11,960
into one, then you actually end
up with only six pieces.

47
00:02:11,960 --> 00:02:13,590
You end up with six pieces.

48
00:02:13,590 --> 00:02:17,720
Hopefully, you see that each row
is one of the pieces now,

49
00:02:17,720 --> 00:02:22,300
and the blue is exactly one
of the six, so 3/18

50
00:02:22,300 --> 00:02:23,550
is the same as 1/6.

51
00:02:23,550 --> 00:02:25,334