Monday, 1 October 2018

F5 Fraction Word Problems Using Models and Common Terms


Fractions Terminology

 Fraction       :                       Numerator
                                             Denominator
                                                              

There are two numbers in a fraction

            n: numerator = how many of the equal parts are shaded
            d: denominator = how many equal parts the total is split into

If the fraction is spelt in words, the numerator Is usually the number and the denominator is expressed with an additional suffix : -th added to another number.

Example: two-fifth -> 2/5

Fraction of a Whole


 Fraction of a Whole with associated Total Number

=>In Model Representation,
            The numerator is the shaded portion
            The total number of squares is the denominator

Comparison Terms (With Associated Total Number)

Using Model to solve  Words Problem/Problem Sums

Example:
There are thrice as many apples as orange.
The word ‘thrice’ is used to describe apples, the nearest object(actor) =>
a. There are 3 apples to every 1 orange
b. When there are 3 apples, there is 1 orange

Example:
There are 3 times more apples than oranges. There are 8 apples. How many oranges are there?

The word ‘3 times’ is used to describe apples. The term ‘more’ can be explained as:
 adding 3  to the existing number  -> 1+3

                
Method:
Step 1:  Who/What and the Numbers? Underline/Circle and write.
Step 2:  What is the story? Draw Model and link
Step 3: (S)olve.


Example
12 fruits are in a basket. There are thrice as many apples as bananas.  How many apples are there?
Step 1 – Who/What and the NumbersUnderline/Circle and write..   => Apple, Banana
            Who/What  number
             Apple
            Banana
Step 2 – What is the story? Draw Model and link
The word ‘thrice’ is used to describe apples. 

There are  thrice   as many   apples   as bananas.
            Who number
             Apple       3u
            Banana     1u
Step 3Solve
There are 12 fruits        
            3u + u = 12 ,
   4u = 12.
      u=3.
 There are 3x3 = 9 apples


Example:
Ali had   2/5 as many stickers as Mary.  Ali has 6 stickers. How many stickers does Mary has?
Step 1 – Who/What and the NumbersUnderline/Circle and write.  => Ali, Mary
            Who  number
             Ali
            Mary
Step 2 – What is the story? Draw Model and link
Ali has 2/5, Mary has 1 -> Ali has 2, Mary will have 5
             Ali          2u
            Mary       5u
Step 3: (S)olve.

            Ali has 6 stickers
            2u = 6
             u = 3

Therefore, Mary has 5x3 = 15 stickers.
Example
There are 4/7  as many adults as children on the bus. There are a total of 33 of them on the bus. How many are children?
Step 1 – Who/What and the NumbersUnderline/Circle and write.  => Adult, children
            Object  number
            Adult
            Children
Step 2 – What is the story? Draw Model and link
   4/7 as many adults as children=> 4 adults to 7 children
             Adult         4u
             Chlldren    7u
Step 3: (S)olve.
Total of 33
            4u + 7u = 33
                  11u = 33
                        u = 3
There are 3 x 4 = 12 children on the bus

Practice

Mary has four times more apples than Peter.  There are 12 apples. How many apples does each has? 

Answer : Mary has 10 apples and Peter has 2 apples.
==========================================================
What is U?
There is usually a certain fixed quantity ‘bundled’(U) together for comparison between the different objects.

Example
There are 3 times more apples than oranges. There are 8 apples. How many oranges are there?
This example can be shown in table form:

Orange
Apple
Unit
1
4
1
2
8
2
3
12
3
4
16
4

The table shows that apples are 3 times more than orange.
Thus for 1 unit there is 1 orange and 4 apples.
For 2 units, there is 2 oranges and 8 apples, etc.
When U=2, there are 8 apples , oranges  = 2.

                      Thus, U defines the “bundled” quantity.
=========================================================