Integers Lesson 4

INTEGERS - Lesson 4
Good morning students.

Textbook to be followed : NCERT

Sources : Youtube

Students you will be able to :

• generalise the meaning of the word additive identity
• produce a pair of integers when their sum is given
• produce a pair of integers when their differnce is given

Explanation

Additive identity when Zero is added to any given integer , the resultant number is always equal to the given integer.

In other words, Zero does not affect any change in an addition expression.

Study the following examples :-

Example 1 :- 4 + 0 = 4

Example 2 :-(- 24 )+ 0 =(- 24)

Example 3 :- 888 + 0 = 888

Example 4 :- 0 + (-33) = (-33)



From the above examples you can learn that sum of Zero and any given integer, always gives the result which is equal to the given integer.

So we can say, Zero has an additive Identity for Whole Numbers

Now let us mentally get ready for looking for a pair of integers which satisfy specific conditions.

*Write down a pair of integers whose sum is (-7)

 

How many such pairs exist?

Did you all say infinite

You are correct. Let us look for atleast 2 such pairs

   - 4 + (-3)

= - 4 – 3                                  … [∵ (+ × - = -)]

= - 7

Some of you might say 0 + (- 7) = (-7)

                                      1 + (-8) = (-7)

The number of such pairs is unlimited.

Now try doing Ex1.2  Q1


*Write a pair of negative integers whose difference gives 8

How many such pairs exist?

Did you all say infinite

You are correct. Let us look for atleast 2 such pairs

Solution:-

= (-5) – (- 13)

= -5 + 13                                 … [∵ (- × - = +)]

= 8

Now try doing Ex1.2  Q2