1
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Find the sum 3 1/8 + 3/4 + ( -2 1/6)

2
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We have two positive numbers, let me draw a

3
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number line , we are going to start with 3 1/8,

4
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this is 0, then we have 1, 2, 3 and then we have 4.

5
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3 1/8 is going to be right over there

6
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3 1/8, is going to be 3 1/8ths to the right of 0

7
00:00:42,267 --> 00:00:49,400
So it is exactly that distance from 0.

8
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The length of this arrow is 3 1/8th.

9
00:00:51,800 --> 00:00:57,533
When ever we have fractions with different denominators

10
00:00:57,533 --> 00:00:59,067
i like to deal them with improper fractions, which

11
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makes addition , subtraction, multiplication easier

12
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So 3 1/8 ths = 25/8

13
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To that we are going to add 3/4ths,

14
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we are going to move another 3/4ths.

15
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to the right , this length is 3/4ths

16
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Where doees this put us, we need to add it.

17
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we have 25/8 + 3/4. The LCM of 4 & 8 is 8

18
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So 3/4 = 6/8.

19
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So it is 25/8 + 6/8 = 31/8

20
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This number right over here is 31/8

21
00:02:34,600 --> 00:02:39,800
32/8 =4 so 31/8 is a bit less than 4

22
00:02:39,800 --> 00:02:52,533
The length of this arrow is 31/8

23
00:02:52,533 --> 00:03:06,067
To write it as a mixed number, 31/8 = 3 7/8ths

24
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Now to that we need to add - 2 1/6

25
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So let us think about waht - 2 1/6ths is like

26
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So we are going to add -2 & - 1/6ths

27
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we can draw -2 1/6ths like this

28
00:03:45,533 --> 00:03:56,133
We can think in a couple of ways, when we add

29
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it is same thing as subtracting 2 1/6ths

30
00:04:18,733 --> 00:04:30,267
This value is going to be difference between 31/8 and - 2 1/6ths

31
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From 31/8, we subtract 2 1/6ths

32
00:04:34,867 --> 00:04:43,800
31/8 - 2 1/6ths

33
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2 1/6 = 13/6

34
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LCM of 8 & 6 is 24

35
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31/8 = 93/24 , and 13/6 = 52/24

36
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So 93/24 - 52/24 = 41/24

37
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It is positive 41 /24

38
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This is little bit less than 2