1 00:00:00,000 --> 00:00:04,390 Let's do some examples comparing absolute values. 2 00:00:04,390 --> 00:00:06,480 So, let's say we were to ask ourselves 3 00:00:06,480 --> 00:00:12,234 how -9, the absolute value of -9 I should say, 4 00:00:12,234 --> 00:00:19,042 how that compares to the absolute value of 5 00:00:19,042 --> 00:00:24,058 -let me think of a good number--the absolute value of -7. 6 00:00:24,058 --> 00:00:25,846 So, let's think about this a little bit and 7 00:00:25,846 --> 00:00:27,912 let's think about what -9 looks like or 8 00:00:27,912 --> 00:00:29,073 where it is in the number line and 9 00:00:29,073 --> 00:00:30,931 where -7 is on the number line. 10 00:00:30,931 --> 00:00:33,671 Let's see where the absolute values mean and 11 00:00:33,671 --> 00:00:36,411 then we should probably be able to do this comparison. 12 00:00:36,411 --> 00:00:38,315 So there are a couple ways to think about it. 13 00:00:38,315 --> 00:00:41,220 One is you can draw them on the number line. 14 00:00:41,220 --> 00:00:45,908 So, if this is 0 and this is -7 15 00:00:45,908 --> 00:00:49,669 and then this is -9 right over here. 16 00:00:49,669 --> 00:00:52,177 Now when you take the absolute value of a number, 17 00:00:52,177 --> 00:00:55,742 you are really saying how far is that number from 0, 18 00:00:55,742 --> 00:00:58,493 whether it is to the left or the right of 0. 19 00:00:58,493 --> 00:01:02,998 So for example, -9 is 9 to the left of 0. 20 00:01:02,998 --> 00:01:07,084 So the absolute value of -9 is exactly 9. 21 00:01:07,084 --> 00:01:16,279 This evaluates to 9. -7 is exactly 7 to the left of 0. 22 00:01:16,279 --> 00:01:20,227 So the absolute value of -7 is +7. 23 00:01:20,227 --> 00:01:22,409 And so, if you were to compare 9 and 7 24 00:01:22,409 --> 00:01:24,081 then this is a little bit more straight forward. 25 00:01:24,081 --> 00:01:29,167 9 is clearly greater than 7. 26 00:01:29,167 --> 00:01:32,278 And if you ever get confused with the greater than and less than symbols, 27 00:01:32,278 --> 00:01:35,645 just remember that the symbol is larger on the left hand side, 28 00:01:35,645 --> 00:01:37,735 so that is the greater than side. 29 00:01:37,735 --> 00:01:41,914 If I were to write this, and this is actually also a true statement. 30 00:01:41,914 --> 00:01:44,190 If you took this without the absolute value signs, 31 00:01:44,190 --> 00:01:49,567 it is also true that -9 is less than -7. 32 00:01:49,567 --> 00:01:53,033 Notice the smaller side is on the smaller number. 33 00:01:53,033 --> 00:01:56,700 And so that is the interesting thing: -9 is less than -7 34 00:01:56,700 --> 00:02:01,024 but their absolute values, since -9 is further to the left of 0, 35 00:02:01,024 --> 00:02:04,507 it is the absolute value of -9 , which is 9, 36 00:02:04,507 --> 00:02:07,900 is greater than the absolute value of -7. 37 00:02:07,900 --> 00:02:09,546 Another way to think about it is 38 00:02:09,546 --> 00:02:11,967 if you take the absolute value of a number, 39 00:02:11,967 --> 00:02:14,770 it really is just the positive value of that number. 40 00:02:14,770 --> 00:02:19,507 So if you took the absolute value of 9 that equals 9. 41 00:02:19,507 --> 00:02:22,967 Or the absolute value of -9, that is also equal to 9. 42 00:02:22,967 --> 00:02:24,198 When you think of it visually, that is 43 00:02:24,198 --> 00:02:27,634 because both of these numbers are exactly 9 away from 0. 44 00:02:27,634 --> 00:02:32,046 This is 9 to the right of 0 and this is 9 to the left of 0. 45 00:02:32,046 --> 00:02:33,857 Let's do a few more of these. 46 00:02:33,857 --> 00:02:37,453 So let's say that we wanted to compare 47 00:02:37,453 --> 00:02:43,749 the absolute value of 2 to the absolute value of 3. 48 00:02:43,749 --> 00:02:47,836 Well the absolute value of a positive is just going to be that same value. 49 00:02:47,836 --> 00:02:52,018 2 is 2 to the right of 0. So this is just going to evaluate to 2. 50 00:02:52,018 --> 00:02:53,900 And then the absolute value of 3, 51 00:02:53,900 --> 00:02:55,567 that is just going to evaluate to 3. 52 00:02:55,567 --> 00:02:57,263 That is actually pretty straight forward. 53 00:02:57,263 --> 00:03:00,833 So 2 is clearly the smaller number here 54 00:03:00,833 --> 00:03:03,167 so we clearly get 2 is less than 3. 55 00:03:03,167 --> 00:03:05,700 Or the absolute value of 2 is less than 3. 56 00:03:05,700 --> 00:03:07,900 So we have a less than right over here. 57 00:03:07,900 --> 00:03:12,633 Let's say you wanted to compare 58 00:03:12,633 --> 00:03:15,933 -I am trying to find a suitable color- 59 00:03:15,933 --> 00:03:19,233 the absolute value of -8 to the absolute value of 8. 60 00:03:19,233 --> 00:03:23,116 One way to think about it is that they are both 8 away from 0. 61 00:03:23,116 --> 00:03:25,916 This is 8 to the left of 0 and this 8 to the right of 0. 62 00:03:25,916 --> 00:03:28,749 So both of these things evaluate to 8. 63 00:03:28,749 --> 00:03:34,183 Absolute value of negative 8 is 8 and absolute value of 8 is 8. 64 00:03:34,183 --> 00:03:38,084 So clearly 8 is equal to 8. 65 00:03:38,084 --> 00:03:39,980 Let's do a couple more examples. 66 00:03:39,980 --> 00:03:46,815 Let's say that I wanted to compare the absolute value of -1 and 67 00:03:46,815 --> 00:03:48,900 I want to compare that to +2. 68 00:03:48,900 --> 00:03:57,967 So the absolute value of -1 is just positive version of -1 which is just 1. 69 00:03:57,967 --> 00:04:00,189 So 1 is clearly less than 2. 70 00:04:00,189 --> 00:04:01,350 Or, the other way to think about it is 71 00:04:01,350 --> 00:04:07,037 the absolute value of negative 1 is clearly less than 2.