1
00:00:00,000 --> 00:00:00,550


2
00:00:00,550 --> 00:00:05,400
Let's add 19 and
3/18 to 18 and 2/3.

3
00:00:05,400 --> 00:00:07,640
So I like to separate out
the whole number parts

4
00:00:07,640 --> 00:00:08,740
from the fraction parts.

5
00:00:08,740 --> 00:00:14,590
So 19 and 3/18 is the same
thing as 19 plus 3/18.

6
00:00:14,590 --> 00:00:18,700
And to that, we are
going to add 18 and 2/3,

7
00:00:18,700 --> 00:00:23,690
which is the same
thing as 18 plus 2/3.

8
00:00:23,690 --> 00:00:26,520
Now we can separately add
the whole number parts.

9
00:00:26,520 --> 00:00:29,295
So we could add
the 19 to the 18.

10
00:00:29,295 --> 00:00:33,210
So we could do 19 plus 18.

11
00:00:33,210 --> 00:00:36,960
And then we can add
the fraction parts--

12
00:00:36,960 --> 00:00:42,896
let me do this in green--
plus 3/18 plus 2/3.

13
00:00:42,896 --> 00:00:46,080


14
00:00:46,080 --> 00:00:48,970
Now 19/18, pretty
straightforward.

15
00:00:48,970 --> 00:00:49,830
That is what?

16
00:00:49,830 --> 00:00:50,330
Let's see.

17
00:00:50,330 --> 00:00:51,739
19 plus 19 would be 38.

18
00:00:51,739 --> 00:00:53,405
So this is going to
be 1 less than that.

19
00:00:53,405 --> 00:00:54,880
It's going to be 37.

20
00:00:54,880 --> 00:00:57,060
So that gives me 37.

21
00:00:57,060 --> 00:00:59,830
And then 3/18 plus
2/3, to add them,

22
00:00:59,830 --> 00:01:01,640
I need to have the
same denominator.

23
00:01:01,640 --> 00:01:05,530
And the least common
multiple of 18 and 3 is 18.

24
00:01:05,530 --> 00:01:09,250
So let's convert 2/3
to something over 18.

25
00:01:09,250 --> 00:01:13,810
So 2/3, if I want to write
it as something over 18,

26
00:01:13,810 --> 00:01:16,550
well, I multiplied
the denominator by 6,

27
00:01:16,550 --> 00:01:19,060
so I'd also have to
multiply the numerator by 6.

28
00:01:19,060 --> 00:01:22,580
So it's the same thing as 12/18.

29
00:01:22,580 --> 00:01:27,390
So I can rewrite 2/3 as 12/18.

30
00:01:27,390 --> 00:01:29,390
And now I can add these
two things together.

31
00:01:29,390 --> 00:01:33,240
That's going to be-- so
I have 37 plus-- it's

32
00:01:33,240 --> 00:01:37,960
going to be something over
18-- plus something over 18.

33
00:01:37,960 --> 00:01:42,452
3 plus 12 is 15, plus 15/18.

34
00:01:42,452 --> 00:01:44,160
And so expressing this
as a mixed number,

35
00:01:44,160 --> 00:01:48,930
I get 37 and 15/18.

36
00:01:48,930 --> 00:01:51,050
And that's the right number.

37
00:01:51,050 --> 00:01:52,520
But we can simplify
it even more.

38
00:01:52,520 --> 00:01:54,160
We can simplify the 15/18.

39
00:01:54,160 --> 00:01:58,330
Both the numerator and the
denominator are divisible by 3.

40
00:01:58,330 --> 00:02:00,084
So let's divide them both by 3.

41
00:02:00,084 --> 00:02:02,000
And we're not changing
the value because we're

42
00:02:02,000 --> 00:02:04,680
doing the same thing to the
numerator and the denominator.

43
00:02:04,680 --> 00:02:09,788
And so this gives us,
we still have our 37,

44
00:02:09,788 --> 00:02:14,400
but the numerator is now 5,
and the denominator is now 6.

45
00:02:14,400 --> 00:02:16,020
So we get 37 and 5/6.

46
00:02:16,020 --> 00:02:19,080


47
00:02:19,080 --> 00:02:20,850
And we're done.