1
00:00:00,440 --> 00:00:06,498
Let's see if we can write 0.15 as a fraction.

2
00:00:06,498 --> 00:00:08,343
So the important thing here is to look at where --

3
00:00:08,343 --> 00:00:10,709
what place these digits are in.

4
00:00:10,709 --> 00:00:13,440
So this 1 right over here, this is in the tenths place.

5
00:00:13,440 --> 00:00:16,608
So you could view that as 1 times 1/10.

6
00:00:16,608 --> 00:00:20,510
This 5 right over here is in the hundredths place.

7
00:00:20,510 --> 00:00:23,800
So you could view that as 5 times 1/100.

8
00:00:23,800 --> 00:00:25,548
So if I were to rewrite this,

9
00:00:25,548 --> 00:00:27,551
I can rewrite this as the sum of --

10
00:00:27,551 --> 00:00:30,003
this 1 represents 1 times 1/10,

11
00:00:30,003 --> 00:00:33,300
so that would literally be 1/10 -- plus --

12
00:00:33,300 --> 00:00:37,107
And this 5 represents 5 times 1/100.

13
00:00:37,107 --> 00:00:40,649
So it would be plus 5/100.

14
00:00:40,649 --> 00:00:41,929
And if we want to add them up,

15
00:00:41,929 --> 00:00:43,914
if we want to find a common denominator,

16
00:00:43,914 --> 00:00:46,086
The common denominator is 100.

17
00:00:46,086 --> 00:00:47,841
Both ten and --

18
00:00:47,841 --> 00:00:51,021
[100] is the least common multiple.

19
00:00:51,021 --> 00:00:52,780
[100] is a multiple of both 10 and 100.

20
00:00:52,780 --> 00:00:59,592
So we can rewrite this as something over 100 plus something over 100.

21
00:00:59,592 --> 00:01:02,730
This isn't going to change. This was already 5/100.

22
00:01:02,730 --> 00:01:05,340
If we multiply the denominator here by 10 --

23
00:01:05,340 --> 00:01:08,180
(That's what we did. We multiplied it by 10.)

24
00:01:08,180 --> 00:01:10,010
-- then we're going to have to multiply this numerator by 10.

25
00:01:10,010 --> 00:01:12,807
And so this is the same thing as 10/100.

26
00:01:12,807 --> 00:01:13,880
And now we're ready to add.

27
00:01:13,880 --> 00:01:20,690
This is the same thing as 10 plus 5 -- is 15 over 100.

28
00:01:20,690 --> 00:01:21,982
And you could have done that

29
00:01:21,982 --> 00:01:23,840
a little bit quicker just by inspecting this.

30
00:01:23,840 --> 00:01:24,680
You would say, "Look!

31
00:01:24,680 --> 00:01:27,200
My smallest place right over here is in the hundredth place.

32
00:01:27,200 --> 00:01:30,810
Instead of calling this 1/10, I could call this literally 10/100.

33
00:01:30,810 --> 00:01:35,490
Or, I could say this whole thing is 15/100.

34
00:01:35,490 --> 00:01:37,770
And now if I want to reduce this to lowest terms --

35
00:01:37,770 --> 00:01:39,146
we can -- let's see --

36
00:01:39,146 --> 00:01:41,810
Both the numerator and the denominator are divisible by 5.

37
00:01:41,810 --> 00:01:44,898
So let's divide them both by 5.

38
00:01:44,898 --> 00:01:48,602
And so the numerator, 15, divided by 5 is 3.

39
00:01:48,602 --> 00:01:51,836
The denominator, 100, divided by 5 is 20.

40
00:01:51,836 --> 00:01:55,658
And that's about as simplified as we can get.