Exponents of decimals — Transcript

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1. 0:00What we're going to do in this video is
2. 0:01get some practice evaluating exponents
3. 0:05of decimals. So, let's say that I have
4. 0:080.2
5. 0:11to the third power. Pause this video,
6. 0:13see if you can figure out what that is
7. 0:15going to be.
8. 0:17Well, this would just mean if I take
9. 0:19something to the third power, that means
10. 0:20I take three of that number and I
11. 0:21multiply them together. So, it's 0.2 *
12. 0:250.2
13. 0:27* 0.2.
14. 0:30Well, what is this going to be equal to?
15. 0:33Well, if I take 0.2 * 0.2, that is going
16. 0:36to be 0.04.
17. 0:40One way to think about it, 2 * 2 is 4,
18. 0:44and then I have one number behind the
19. 0:46decimal to the right of the decimal
20. 0:47here. I have another digit to the right
21. 0:48of the decimal right over here. So, my
22. 0:50product is going to have two digits to
23. 0:53the right of the decimal. So, it'd be
24. 0:540.04.
25. 0:56And then if I were to multiply that *
26. 0:580.2, so if I were to multiply that
27. 1:01together, what is that going to be equal
28. 1:03to? Well, 4 * 2 is equal to 8. And now I
29. 1:08have
30. 1:10two, three numbers to the right of the
31. 1:12decimal point. So, my product is going
32. 1:15to have one,
33. 1:16two, three numbers to the right of the
34. 1:19decimal point.
35. 1:21So, now that we've had a little bit of
36. 1:22practice with that, let's do another
37. 1:24example.
38. 1:25So, let's say that I were to ask you,
39. 1:28what is 0.9
40. 1:34squared?
41. 1:36Pause this video and see if you can
42. 1:37figure that out.
43. 1:39All right. Well, this is just going to
44. 1:41be 0.9
45. 1:43* 0.9.
46. 1:46And what's that going to be equal to?
47. 1:48Well, you could just say 9 * 9 is going
48. 1:51to be equal to 81.
49. 1:54And so, let's see, in the two numbers
50. 1:56that I'm multiplying, I have a total of
51. 1:58one, two numbers or two digits to the
52. 2:01right of the decimal point. So, my
53. 2:03answer is going to have one, two digits
54. 2:05to the right of the decimal point. So,
55. 2:07I'd put the decimal right over there and
56. 2:09I'll put the zero. So, 0.81. Another way
57. 2:12to think about it is 9/10 of 9/10 is
58. 2:1581/100.
59. 2:17But, there you go. Using exponents or or
60. 2:20taking exponents of decimals is the same
61. 2:22as when we're taking it of integers.
62. 2:25It's just in this case, you just have to
63. 2:26do a little bit of a decimal
64. 2:28multiplication.