## anonymous one year ago What is 1 1/2 x3

1. anonymous

it is $\huge 1\tfrac{1}{2}\times 3$

2. anonymous

yes

3. anonymous

do you know how to write $\huge 1\tfrac{1}{2}$ as an "improper fraction"? that is the first step

4. anonymous

a little

5. UsukiDoll

so first we have do deal with the 1 x 2 portion so what's 1 x 2 ?

6. anonymous

I got 3/2

7. anonymous

good

8. UsukiDoll

correct.

9. anonymous

then $\frac{3}{2}\times 3$ completes it

10. anonymous

remember "multiply" means multiply in the numerator (top) so $\frac{3}{2}\times 3=\frac{3\times 3}{2}$

11. UsukiDoll

$\LARGE \frac{3}{2} \times 3$ now all we have to do is to multiply $\LARGE \frac{2}{2}$ to 3 so we can have fractions with the same numerator x.x

12. anonymous

oh no!!!

13. anonymous

i got 6

14. UsukiDoll

what?

15. anonymous

@UsukiDoll c'mon! you know you do not need a common denominator to multiply fractions !!!

16. anonymous

I also got 18

17. anonymous

lets go slow

18. UsukiDoll

nugh. this guy -_-

19. UsukiDoll

sigh.. let me guess change 3/2 into a decimal and then multiply by 3 ?

20. anonymous

no no just multiply

21. anonymous

we are at this step $\frac{3}{2}\times 3$ right?

22. anonymous

6

23. anonymous

there is no 6 in it

24. anonymous

i multiplied and got 6

25. anonymous

$\frac{3}{2}\times 3=\frac{3\times 3}{2}$ where does the 6 come from?

26. anonymous

then I multiplied and got 18

27. UsukiDoll

wait a sec. re-write this a bit. to what sat wrote

28. anonymous

okay

29. anonymous

in the numerator (top) you have $$3\times 3$$ which is ?

30. anonymous

9

31. anonymous

right

32. UsukiDoll

so the numerator is 9 and the denominator is 2 which is 9/2

33. anonymous

and in the denominator you have just the 2

34. anonymous

okay

35. anonymous

giving you $\frac{9}{2}$ which you should probably then write as a mixed number since you started with mixed numbers

36. anonymous

4 1/2

37. anonymous

at the risk of repeating myself you do NOT find a common denominator when multiplying that is for addition or subtraction multiply means multiply, that is all

38. anonymous

right

39. UsukiDoll

wow are you kidding me right now sat? $\large \frac{3}{2} \times 3 \cdot \frac{2}{2}$ $\large \frac{3 \times 6}{4} \rightarrow \frac{18}{4} \rightarrow \frac{9}{2}$

40. anonymous

that is $\huge 4\tfrac{1}{2}$ is correct

41. anonymous

@UsukiDoll you must be kidding me right?

42. anonymous

okay

43. UsukiDoll

no. even with finding the common denominator we can still get the same result -_-

44. anonymous

$\frac{3}{2}\times 3\times\frac{100}{100}=\frac{3\times 300}{200}=4\tfrac{1}{2}$

45. UsukiDoll

heck if I was given that option to do it that way, pfffffffft so be it XD

46. anonymous

you are doing nothing but confusing the issue you can get an equivalent fraction for 3 by multiplying top and bottom by any number you choose, but you do not do that when multiplying

47. UsukiDoll

no I'm not. I'm making it easier by having common denominators all over the place, so I can simplify the numerator... combine the denominator and then reduce.

48. anonymous

let me repeat myself you do NOT find a common denominator when multiplying you need that only for addition and subtraction multiply means multiply

49. anonymous

$\frac{a}{b}\times \frac{c}{d}=\frac{ac}{bd}$ that is all

50. UsukiDoll

ahahaha you just did fractions XD

51. anonymous

yes of course

52. anonymous

$\frac{a}{b}\times c=\frac{ac}{b}$ also fractions

53. UsukiDoll

$\frac{a}{b}\times \frac{c}{d}=\frac{ac}{bd}$ this is better.

54. anonymous

they are the same, only in the second case $\frac{a}{b}\times c$ you have $$d=1$$ no common denominator needed

55. anonymous

okay

56. UsukiDoll

exactly sat .. still using fractions XD

57. anonymous

let me ask you @UsukiDoll do you really build up fractions when multiplying? how would you compute $\frac{52}{17}\times 5$?

58. UsukiDoll

$\frac{52}{17}\times 5 \cdot \frac{17}{17}$ $\frac{52}{17} \times \frac{85}{17} \rightarrow \frac{4420}{289}$

59. anonymous

at least you are being consistent!

60. anonymous

some times people have different methods that still give you the same answer

61. anonymous

why not $\frac{52}{17}\times 5 \cdot \frac{23}{23}$? that will work as well

62. Loser66

@UsukiDoll is it right?$$3=\dfrac{3}{1}$$? why do we have the common denominator on multiplication ?

63. UsukiDoll

so agree with @Aliypop

64. misty1212

i like $\frac{52}{17}\times 5 \cdot \frac{1712}{1712}$

65. anonymous

66. misty1212

$\frac{52}{17}\times 5=\frac{52\times 5}{17}$

67. misty1212

so your real job is to compute $$52\times 5$$ don't mess with mr 17

68. anonymous

don't mess with mister inbetween?

69. anonymous

so would I multiply

70. UsukiDoll

that's just some example fraction that they threw at me. the real answer is already done. Honestly that's what I was taught in elementary school and it worked well. NO one is going to force me to use whatever kind of jumbo shrimp thing they throw out there. If it worked millions of times, I'm not going to change it!

71. UsukiDoll

P.S $\frac{4420}{289} = 15.29$ $\frac{52}{17}\times 5 = 3.058 \times 5 = 15.29$ oh look ! The same decimal value regardless of method. nughhhhhh. . . sorry for ranting but that had gone too far.

72. anonymous

thank for so much for helping me @UsukiDoll

73. UsukiDoll

you're welcome @Aliypop :) It's after 4 am... I better get some sleep.

74. anonymous

okay

75. UsukiDoll

night everyone.