CLASS-7
ADDITION OF INTEGERS ON NUMBER LINE

Addition of Integers On Number Line

RULES FOR ADDITION OF INTEGERS:-

1) To add positive integer +x, move x unit to the right of the given integers. 

2) To add negative integer –x, move x units to the left of the given integers.     

The Other rules for addition of integers are:-

1) To add two positive integers:-   Add them as natural numbers.

2) To add two negative integers:-  Ignore their signs,find the sum of the numbers and give negative sign to the sum obtained.

3) To add a positive integer and a negative integer:-  Ignore their signs,subtract the smaller number from the larger number and give the sign of the integer which has the larger absolute value to the result obtained.

The rules for addition/subtraction of integers using number line are:-

i) To add a positive integer,move to the right on the number line.

ii) To add a negative integer,move to the left on the number line.

iii) To subtract a positive integer,move to the left on the number line.

iv) To subtract a negative integer,move to the right on the number line.

ADDITIVE INVERSE OF AN INTEGER:-

For every integer ‘a’,there exists integer -a such that:-

                        a + (-a) = 0 = (-a) + a

Thus, -a is the additive inverse of ‘a’ and ‘a’ is the additive inverse of -a. Hence, -(-a) = a.

If ‘a’ and ‘b’ are two integers,then a + b = b + a.

If a, b and c are any three integers,then (a + b) + c = a + (b + c)

To add a negative integer to a given integer, move to the left of the given integer by as many unit distance as the absolute value of the integers to be added. From (+4) we move to 3 unit to the left and arrival at 1.

Then  (-3) + ( 4) = 1 

Add a positive integer to a given integer, move to the right of the given integer by as many unit distances as the absolute value of the integer to be added. From (+3) we move 5 units to the right and arrive at 8.

Then  (+3) + (+5) = 8