Saturday, February 26, 2011

Multiplying Mixed Numbers

Hi, kids. Welcome to the second e-tivity of this academic year. I am sure you will have a great time. This e-tivity is about multiplying mixed numbers, by the end you will be able to
  • understand what multiplication is &
  • explain to your classmates what procedures to follow when multiplying mixed numbers.
Average online time: 20 min
Average offline time: 10 min

1- Getting Started

Write down in the following shoutbox what you know about fractions. After writing your message, click the send button


2- Understanding what Multiplication Entails
Keep in mind the following facts:

1) Multiplying can be seen as taken a number "x" times, so for instance 3 x 4 means that you take the number "3" four times. In other words, you add 3 + 3 + 3 + 3

2) The result of a multiplication is called the product and the numbers being multiplied are called factors. For instance, in the mathematical sentence 3 x 4 = 12, 
3 and 4 are the factors & 12 is the product

3) When two numbers are multiplied together, the product is the same regardless of the order of the factors.
7/3 x 4/5 = 4/5 x 7/3

4) The product of any number and 1 is that number.
1/3 x 1 = 1/3 

3- Multiplying Mixed Numbers
Method 1
As you watch the following video, write down the steps the teacher uses to multiply two mixed numbers


Method 2
As you watch the following video keep in mind that a mixed number can be written as a whole number plus a fraction. For instance 


In addition,  when you multiply mixed numbers you can use what is called the distributive property.
  

Ready to watch the second video?



4- Checking Understanding
What would be the answer of the following multiplication.
Click here to check your answer.


5- Assessing Understanding: 
GIF animations generator gifup.com
Select any two mixed numbers and following whether method 1 or method 2 multiply them.
Write down your answer and explain how you got it. 

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35 comments:

  1. AnonymousFebruary 28, 2011 at 3:13 p.m.

    the teacher multiply the denominator times the whole number and add the numerator to make it a improper fraction then multiply the improper fractionand then divide it.am juan camilo

    ReplyDelete
  2. gabriela tovarFebruary 28, 2011 at 3:24 p.m.

    3 1/4 * 1 2/3 = 3 2/12

    using the method number one.

    ReplyDelete
  3. alejandro ortegaFebruary 28, 2011 at 3:59 p.m.

    5 5/12 x 3 2/6 =18 1/18

    ReplyDelete
  4. alejoFebruary 28, 2011 at 4:36 p.m.

    method 1
    5 5/6 x 3 2/6
    35/6 x 20/6
    6/6 x 2/6= 12/36

    ReplyDelete
  5. Alethia,February 28, 2011 at 7:09 p.m.

    Hi kids, nice to see you around.
    Juan Camilo, you need to provide an example.
    Gabriela, you need to revise your procedure.
    Alejandro Ortega, well done :).
    Alejo please revise your procedure (multiply 35/6 and 20/6)
    Thanks!

    ReplyDelete
  6. cesar olarteFebruary 28, 2011 at 8:38 p.m.

    4 1/5 x 2 2/3

    21/15 x 8/15=168/15
    168/15=168 divided by 3= 56 56/5
    15 divided by 3= 5

    5:10,15
    3:6,9,12,15

    ReplyDelete
  7. Maria CamilaFebruary 28, 2011 at 9:03 p.m.

    Method 1:

    2 4/5 x 3 1/2 = 14/5 x 7/2 = 49/5 = 9 4/5

    ReplyDelete
  8. Alethia,March 1, 2011 at 6:48 a.m.

    Ma Camila, well done
    Cesar, revise your procedure ( 2 2/3 = 8/3)
    See you around!

    ReplyDelete
  9. andres mendezMarch 1, 2011 at 4:29 p.m.

    3 6/3 + 6 7/4 = 15/3 24/4 miss i dont understand so much.

    ReplyDelete
  10. AnonymousMarch 1, 2011 at 4:49 p.m.

    5 3/5 x 8 3/2 change to improper fraction 28/5 x 19/2 then i simplify 14/5x19/1 = 266/5
    then i convert to mixed number dividing 266 between 5 = 53 rest 1
    then i write 53 1/5

    Atte Wiiliam de La Hoz

    ReplyDelete
  11. santi duarteMarch 1, 2011 at 5:31 p.m.

    I am going to multiply 3 1/2 X 4 1/2. first i changed it into improper fraction, and the answer is 7/2 X 9/2. the answer is 63/2. the numbver is improper fraction so you need to change it into mixed number.tou need to devide 63 devided by 2 that is 2 3/12 :)

    ReplyDelete
  12. Silvia MejiaMarch 1, 2011 at 5:37 p.m.

    Method#1:

    3 2/4 x 2 2/5
    3 2/4=14/4 2 2/5=12/5
    14/4 x 12/5 = 42/5 = 8 2/5

    ReplyDelete
  13. Alethia,March 1, 2011 at 5:47 p.m.

    William and Silvia, well done!
    Santi, the first step is okay. The second step though needs to be revised. 7/2 x 9/2 is not equal to 63/2 (you need to multiply both numerators and both denominators).
    Andrés, watch the second video again and try to follow the same steps the teacher does. You could also look at William's and Silvia's posts.
    See you around

    ReplyDelete
  14. Julian DuarteMarch 1, 2011 at 5:55 p.m.

    My number is 3 4/6 and 2 3/5 so the first step is to change it into an improper fraction: 3 4/6=22/6 and 2 3/5=13/5, now we multipy it horizontaly like this: 22/6x13/5=286/30 and we can simplify it like this:286/30=143/5.
    Julian Duarte

    ReplyDelete
  15. AnonymousMarch 1, 2011 at 6:09 p.m.

    Method 1:
    2 4/5 x 3 1/2 = 14/5 x 7/2 = 49/5 = 9 4/5

    ReplyDelete
  16. AnonymousMarch 1, 2011 at 6:09 p.m.

    att angela peña

    ReplyDelete
  17. Alethia,March 1, 2011 at 6:12 p.m.

    Angela, well done!
    Julián, 286/30 is okay. If you simplify, you need to divide both the numerator and the denominator by the same number, if at the end you've got an improper fraction you need to convert it into a mixed number.

    ReplyDelete
  18. MATEOMarch 1, 2011 at 7:09 p.m.

    2 3/4 x 1 4/6:
    2x3=6+3=9 9/4.
    1x6=6+4=10 10/6.
    9/4 x 10/6= 90/24= 3 3/4
    9x10=90 and 4x6=24 so the answer id 90/24 but simplifying by 3 equals 30/8 divided by 2 equals 15/4 so now i need to change this fraction to a mix number so that mixed number is 3 3/4 because 4 is 3 times in 15 because 4x3=12 and to get 15 i need 3 more so i added and it gives me 3 3/4.

    ReplyDelete
  19. AnonymousMarch 1, 2011 at 7:15 p.m.

    My mixed #s are: 1 2/5 & 2 1/3.Im going to use method 1 So 4 2/5 = 22/5 & 2 1/3 = 7/3.7/5 x 7/3 = 49/15 = 4 5/15
    From: Carlos Trujillo

    ReplyDelete
  20. Isa GomezMarch 1, 2011 at 7:57 p.m.

    work: 5 2/3 x 4 1/2 :
    17/3 x 9/2 :
    17/1 x 3/2: 51/2
    25 1/2

    ReplyDelete
  21. juan andres de los riosMarch 1, 2011 at 8:00 p.m.

    I have 3 1/3 and 4 1/3.first I need to change to a improper friction:7/3 and 13/3. i multiply 7/3x12/3=84/3.if the fraction is a improper friction I need to change to a mix number.the mix number is 28 0/3.
    if we can simplify we simplify

    ReplyDelete
  22. AndresMarch 1, 2011 at 8:01 p.m.

    first we need to multiply the whole number by the denominator and then we add the numerator so the numerator is the anser and the denominator stais the same and then we multiply across and thats the answer.

    ReplyDelete
  23. veroMarch 1, 2011 at 8:28 p.m.

    Method 1
    1 5/8 times 2 3/6 = 13/8 times 15/8 = 195/63 = 3 6/63

    Is very easy,you need need first to change the mix number to improper and then i multiply the numerator by the numerator and the denominater to the denominater.

    ReplyDelete
  24. AnonymousMarch 1, 2011 at 8:52 p.m.

    Method #1:

    4 2/4 x 5 1/3
    4 2/4= 18/4 5 1/3= 16/3
    18/4 x 16/3 = 72/3= 24

    Maria Paula Donoso 5B

    ReplyDelete
  25. lourdes manrique 5bMarch 1, 2011 at 9:33 p.m.

    so 1sth my numbers are 4*2/3 and the other is 3*4/5
    and then you do this

    you need to change this numbers to improper fractions so 4*2/3 you changed like this 4 the whole number by 3 the denominator and the add the 2 that is the numerator and its 14/3 and with the other that it will be 19/5 and then you multiply 14/3 x 19/5= 14/1 x 6/5 =84/5 and then you changed to mix number 16*4/5
    thanks
    lourdes manrique 5b

    ReplyDelete
  26. Andres AriasMarch 2, 2011 at 4:20 p.m.

    first we need to multiply the whole number by the denominator and then we add the numerator so the numerator is the anser and the denominator stais the same and then we multiply the denominator by the denominator and the numerator by the numerato and thats the answer

    ReplyDelete
  27. Juan Pablo VacaMarch 2, 2011 at 4:59 p.m.

    1st sorry for giving it late :[

    so, my numbers are 2 7/9 & 7 1/3
    so, i need to change to improper fractions the 2 numbers, 1st 2 7/9 so, 2 times 9 plus 7 equal 25/9, and 7 1/3 , so 7 times 3 plus 1 equal 22/3.
    so, then i multiply 22/3 times 25/9 equal 550/27, but then i need to change it to mixed number so it would be 20 10/27

    thanks miss alethia
    juan pablo vaca

    ReplyDelete
  28. Julian DuarteMarch 2, 2011 at 6:21 p.m.

    correction:286/30=143/30

    ReplyDelete
  29. AnonymousMarch 2, 2011 at 7:58 p.m.

    My number is 4 1/2 and 8 3/4 so I need to change my numbers to improper fractions so I multiply 4 times 2 and then I add 1 so it will be 9/2 & the same with the other one so it will be 35/4 then I simplify them and it will be 315/8 and then i change it to an mixed number so it will be 312 3/8
    thanks miss
    Juan Felipe Velez

    ReplyDelete
  30. Tabata TamayoMarch 2, 2011 at 11:52 p.m.

    IT GIVE ME 7.
    I AM GOIN TO SHOSE 3 2/5 MULTIPLYING 2 1/2 Icual 8 9/2 first i combert the mix number and i multiply and then i convert the numer again to a mix number to put the resolt.

    ReplyDelete
  31. manuela hernandez bonettMarch 7, 2011 at 3:36 p.m.

    2 4/5 x 4 1/2 = 16/5 x 7/2 = 51/5 = 12 4/5
    the teacher give mixed # we change them an we do all these procidures but whit their #.
    ATT:manu hernandez

    ReplyDelete
  32. alejandra salasMarch 7, 2011 at 7:30 p.m.

    i use method 1
    3 2/4 x 2 2/5
    3 2/4=14/4 2 2/5=12/5
    14/4 x 12/5 = 42/5 = 8 2/5
    i think that is like his.

    maria alejandra salas millan

    ReplyDelete
  33. Tabata TamayoMarch 8, 2011 at 7:38 p.m.

    4 1/5 X 2 2/3=
    so first you change to improper fractions o is 5X4=20+1=21 but is the same denominator so is 21/5 an the other is 3X2=6+2=8 so the fraction is 8/3 so then you multiply 21/5 X 8/3=168/15 so then you change to a mix fraction like this 168 divided 15 =11 3/15

    ReplyDelete
  34. OLGUISF VARONMarch 21, 2011 at 3:34 p.m.

    hi miss:
    this is the work that i do.i do it now because i was sick.

    my 2 # are 3 2/4 and 4 5/6.
    first i need to changed to improper so 3 2/4=13/4 and 4 5/6 = 29/6.then i need to multiply the improper fractions so 13/4 x 29/6 = 377/24 and then i need to changed again to mixed so the answer will be :10 137/24
    GOOD NIGHT MISS
    OLGA FERNANDA VARON RUGELES

    ReplyDelete
  35. AnonymousApril 19, 2011 at 2:05 p.m.

    I've got a problem here... it says:
    Consider the positive integer that is written 2011, 2011 times (the number begins 201120112011...2011). Express this number as a product (multiplication)of two positive integers with at least three digits each. (So this means it could be larger than three digits, but at least 3).
    What is the answer?!

    ReplyDelete

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