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    Multiplying Dividing Fractions

    Uploaded by

    John Deniel Gonzales
    This document discusses multiplying and dividing fractions. It explains that when multiplying fractions, you multiply the numerators and denominators. When dividing fractions, you turn the dividing fraction upside down and multiply the numerators and denominators. It provides examples of multiplying and dividing fractions, mixed numbers, and fractions with whole numbers. It also discusses cancelling terms before multiplying or dividing and explains that multiplying always makes quantities larger while dividing always makes quantities smaller.

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    © All Rights Reserved
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    Multiplying Dividing Fractions

    Uploaded by

    John Deniel Gonzales
    25 views24 pages
    This document discusses multiplying and dividing fractions. It explains that when multiplying fractions, you multiply the numerators and denominators. When dividing fractions, you turn the dividing fraction upside down and multiply the numerators and denominators. It provides examples of multiplying and dividing fractions, mixed numbers, and fractions with whole numbers. It also discusses cancelling terms before multiplying or dividing and explains that multiplying always makes quantities larger while dividing always makes quantities smaller.

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    multiplying_dividing_fractions (2)

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    This document discusses multiplying and dividing fractions. It explains that when multiplying fractions, you multiply the numerators and denominators. When dividing fractions, you turn the dividing fraction upside down and multiply the numerators and denominators. It provides examples of multiplying and dividing fractions, mixed numbers, and fractions with whole numbers. It also discusses cancelling terms before multiplying or dividing and explains that multiplying always makes quantities larger while dividing always makes quantities smaller.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    25 views24 pages

    Multiplying Dividing Fractions

    Uploaded by

    John Deniel Gonzales
    This document discusses multiplying and dividing fractions. It explains that when multiplying fractions, you multiply the numerators and denominators. When dividing fractions, you turn the dividing fraction upside down and multiply the numerators and denominators. It provides examples of multiplying and dividing fractions, mixed numbers, and fractions with whole numbers. It also discusses cancelling terms before multiplying or dividing and explains that multiplying always makes quantities larger while dividing always makes quantities smaller.

    Copyright:

    © All Rights Reserved
    Download as PPTX, PDF, TXT or read online from Scribd
    Download as pptx, pdf, or txt
    of 24

    MULTIPLYING AND

    DIVIDING FRACTIONS
    Can you name the parts of a
    fraction?

    3
     

    ?
    numerator

    ?
    denominator
    4
    What sort of fractions / numbers are these:

     
    7
    ?
    proper fraction
    8  
    3
    ?
    mixed number
    2
    8
     
    9
    ?
    improper fraction
    7
     
    Multiplying Fractions

    2×3 6  
    1
    ×= 3×4
    = 12 = 2

    1. Multiply the numerators.


    2. Multiply the denominators.
    3. Cancel down.
       
       
    ×= = ×= =

    ×= ×= =

    ×= = ×=

    ×= ×= =
     
    Multiplying mixed numbers.

     
    2×    
    = × = =

    1. Change the mixed number to an improper fraction.


    2. Multiply as before.
    3. Cancel down and change to mixed number if necessary.
       

    1×= × =

    2×=  
    × = =1
    × 1=  
    × = =1
    1 × 1=
     
    × = = =2
     
    Multiplying fractions and whole numbers

       
    12 × = × =  
    10
    1. Whole numbers have a denominator of 1.
    2. Multiply numerators and denominators.
    3. Cancel down and change to a mixed number
    if necessary.
     
     
    ×6=

    × 12 =

    5× =

    ×4=

    7× =
     Cancelling down.

    It is often easier to cancel down before you multiply.


    When you are multiplying fractions, any numerator can be
    cancelled against any denominator.
    After multiplication

    × = =
    Before multiplication

    1
    × = 2
      2
    5
    5
    1
     
    Cancelling after multiplication

    × = =

    Cancelling before multiplication


    1 4
        4
    × = 21
    3 7

    Which is easier?
    Multiplying always makes things bigger:

    2x3=6

    6 is bigger than both 2 and 3

    Is he
    correct?
     
    If you multiply a number by 1,
    it does not increase or decrease.

    3x1=3

    If you multiply a number by 0, you get 0

    3x0=0

    If you multiply a number larger than 1 by a proper


    fraction, the product is less than the original number.

    4 x = 2 (2 < 4)
     Ifyou multiply two proper fractions together, the product
    is less than either of them:

    × =

    of means ×

     
    of =  
    of =

    = =
     
    Dividing Fractions

    ÷   3
      1    
    = ÷× 13 = =

    1. Turn the dividing fraction upside down


    and change ÷ to ×.
    2. Multiply numerators and denominators.
    3. If necessary cancel down and change to
    a mixed number.
        4
      1  
    =
     
    =
    ÷ = ÷× 14
     
    ÷ 3    2
      5  
    =  
    = ÷
    × =
    7 52
     
    ÷
      3  81  
    =  
    = 4 ÷
    ×
    1
    8
    =
     
    ÷
      5 ×  3
    1  
    = =
     
    = ÷ 13
    6
        4  1
    2  
    ÷ = 9
    ÷
    ×
    2
    =
    1
     
    Dividing mixed numbers.

       
    2÷ = ÷  
    = × = =

    1. Change the mixed number to an improper fraction.


    2. Divide as before.
    3. Cancel down and change to a mixed number if
    necessary.
       
    1 ÷ = × = =5
       
    2 × = =3
       
    3 × = =9

       
    31 × = =3

       
    1 × = =
     
    Dividing fractions and whole numbers

     
    35
          
    1
    8÷ = ÷× = ¿ 13
    53 3

    1. Whole numbers have a denominator of 1.


    2. Turn dividing fraction upside down and
    multiply numerators and denominators.
    3. Cancel down and change to a mixed number
    if necessary.
       
    =

    =
    Division always makes things smaller. If I divide up a
    rich, tasty chocolate cake, I always get a smaller
    piece than the whole cake.

    12 ÷ 4=3

    3 is less than 12

    Is she
    correct?
     
    If you divide a number by 1,
    it does not increase or decrease.

    3÷1=3

    If you divide 1, or a number larger than 1, by a proper


    fraction, the answer is greater than the original number.

    4 ÷ = 8 (8 > 4)
     
    If you divide a larger fraction by a smaller
    one, the answer will be more than 1.

    ÷ =6

    ÷ =6

     
    How many are there in ? 6
    The end

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