CBSE CLASS 3 MATHS CHAPTER 10 FRACTIONS

  
  FRACTIONS
   When a thing is divided into equal parts each part is called a fraction of the whole(the full thing).

   Half
     When something is divided into two equal parts ,each part is one half of the whole.
     One half is written as 1/2.
     To write a fraction in numbers,we write          number of parts chosen
                                                                           total number of equal parts
  One Third
    When something is divided into three equal parts,each part is one third(1/3)of the       whole.
    Two one thirds together make two thirds(2/3).
    Three one thirds together make the whole.
  One Fourth
   When something is divided into four equal parts,each part is one fourth(1/4)of the whole.
   One fourth is also called a quarter.
   
   To find half of a number ,divide by 2
   1/2 of 4=2   1/2 of 8=4   1/2 of 12=6

   To find one third of a number , divide by 3
   1/3 of 6=3   1/3 of 9=3   1/3 of 12=4

   To find one fourth of a number , divide by 4
   1/4 of 8=2   1/4 of 12=3  1/4 of 20=5

Fill in
   1/2 of 4   =   8     1/2 of 12   =     6    1/3 of of 9=    3    1/5 of 10=    2    1/9 of 18=   2
                     -------                    --------                   --------                --------                -------- 
   One third of 18=       6     A quarter of 16=         4         One sixth of 24=    4 
                                --------                               ----------                               --------  
   In 3/4 the numerator is  3  and the denominator is  4.
                                        ----                                     -----
   In 7/9 the numerator is  7  and the denominator is  9.
                                        ----                                   -----
  The fraction whose numerator is 4 and denominator is 7 is 4/7.
                                                                                               ------
  The fraction whose numerator is 11 and denominator is 13 is   11/13
                                                                                                      --------

1. Nine Children went for a picnic.One third of them were girls,how many boys were there?
A. Total number of children=9
     Number of girls            =  1/3 of 9
                                           =  1/3 * 9
                                           =  3
     So number of boys        =  9-3=3
  
2.  Ajay read one fifth of a 100-page book.How many pages of the book did he read?
A. Total number of pages            =  100
      Number of pages Ajay read  =  1/5 of 100
                                                    =  1/5 *100
                                                    =  20
            
3. An hour has 60 minutes.How many minutes is aquarter of an hour?
A. 1 hour = 60 minutes
     Quarter of an hour=1/4 of an hour=1/4 of 60 minutes
                                    =1/4 *60
                                    =15 minutes
    
4.  Ali shared 1 litre of pineapple juice equally with three friends.How much did each friend get?
A. Amount of pineapple juice  =  1 litre / 1000ml
    Total number of members    =  4(including Ali)
    Amount of pineapple juice each friend get=1/4 litre or 1000/4 ml
                                                                       =1/4 litre or 250 ml
   
5. Eight children shared a pizza equally.What fraction of the pizza did each child get?
A. Total number of children   =  8
     Fraction of the pizza each child get=1/8

6. Jyothi had 24 sweets.She gave one third of them to Vijaya.How many sweets were left?
A. Number of sweets           =  24
     Number of sweets she gave to Vijaya=1/3 of 24
                                                                 =1/3 *24
                                                                 =8
    Number of sweets left                           =24-8=16
7. Swathi has watered one fourth of her plants.If she has 16 plants,how many more plants does she          have to water?
A. Total number of plants     =  16
     Number of plats swathi watered=1/4 of 16
                                                        =1/4 *16
                                                        =4
    Number of plants she has to water=16-4=12