# CLASS-7MULTIPLICATION OF INTEGERS

Multiplication of Integers

The product of two integers of the same sign is a positive integer equal to the product of the absolute value of the integers. The product of two integers of opposite sign is a negative integer, whose absolute value is equal to the product of their absolute value.

If, a, b, c are the integers

1)  a X b = b X a

2)  0 X a = a X 0 = 0

3)  1 X a = a X 1 = a

4) a X (b + c) = (b + c) X a = (a X b) + (a X c)

Multiplication of positive integers –

The product of two integers of the same sign is a positive integer equal to the product of the absolute value of the integers.

Example.1)  (+12) X (+9)  = + (12 X 9) = + 108

Example.2)  (+115) X (+12) = + (115 X 12) = + 1380

Example.3)  (+110) X 0 = 0 X (+110) = 0

Example.4)  (+175) X 1 = 1 X (+175) = +175

Multiplication of negative integers –

The product of two integers of opposite sign is a negative integer, whose absolute value is equal to the product of their absolute value, multiplication of integers is commutative –

Example.1)  (+12) X (-50) = - (12 X 50) = - 600

Example.2)  (-10) X (-45) = + 450  (Multiplication of two negative                                              integers provides positive integers)

Example.3)  (-280) X 0 = 0 X (-280) = 0

Example.4)  (-18) X 1 = 1 X (-18) = -18