Download THE NUMBER SYSTEM

Unit 1 The Number System
1.2.5 The Four Operations on Real Numbers
The following activity is designed to help you revise the four operations on the set of
rational numbers which you have done in your previous grades.
ACTIVITY 1.12
1
Apply the properties of the four operations in the set of rational
numbers to compute the following (mentally, if possible).
2
a
2 3 7
+ + 
9 5 9
b
3  −11   −3   −11 
×
 +  

7  21   7   21 
c
3  5 −3 
+ + 
7 6 7 
d
 −9 23   −7 
×

×

 7 −27   9 
State a property that justifies each of the following statements.
a
−2  3 3   − 2 3  3
 ×  =  × ×
3  2 5  3 2 5
c
−3 −1
 − 3   − 5   − 1   −5 
  +   <   +   , since 5 < 5
 5   6   5   6 
b
−7  3 −4  −7  −4 3 
+ 
 +
= 
9 2 5  9  5 2
In this section, you will discuss operations on the set of real numbers. The properties
you have studied so far will help you to investigate many other properties of the set of
real numbers.
Group Work 1.6
Work with a partner
Required:- scientific calculator
1
Try this
Copy and complete the following table. Then use a calculator to find each product
and complete the table.
Factors
3
product
product written as a power
2
2 × 2
101 × 101
3
 −1   −1 
 × 
 5   5 
37