1. One to One= A function 1  5 2 6 3  7 4 8  5 9  
The Rule is ‘ADD 4’

2. Not a function Paris Ahmed  London Peter Dubai Ali  New York Jaweria
Cyprus
Ahmed
Peter
Ali
Jaweria
Hamad    
Has Visited
There are MANY arrows from each person and each place is related to MANY
People. It is a MANY to MANY relation.

3. FUNCTION       Person Has A Mass of Kg Bilal 62 Peter Salma 64
Alaa
George
Aziz 62 64 66     
In this case each person has only one mass, yet several people have the same
Mass. This is a MANY to ONE relationship

4. Not a function Is the length of cm object  Pen Pencil Ruler Needle
Stick  14 30   
Here one amount is the length of many objects.
This is a ONE to MANY relationship

5. FUNCTIONS
Many to One Relationship
One to One Relationship

6. Function - Domain and Range!
x2x+1 A B 1 2 3 4 1 3 5 7 9
Domain Range

7. Which Are Functions?
(b)
(a)
(c)
(d)
(a) and (c)

8. Which Are Functions?
(b)
(a)
(c)
(d)
(a) and (c)