Integers - Class 7 Maths

Integers - Integers are numbers that contain whole numbers and negative numbers, integers are not fractions or decimal numbers.

Whole numbers - Whole numbers are numbers that start from 0

Negative numbers - Negative numbers are numbers that have minus sign before them

Additive inverse - Additive inverse of a number simply means changing the sign of the number
    Example: Additive inverse of 5 is -5
             Additive inverse of -5 is 5

Properties of Integers

• Closure Property
• Cummulative Property
• Identity Property
• Associative Property
• Distributive Property

There are four integer operations

• Addition
• Subtraction
• Multiplication
• Division

Points to remember regarding sign

• If we have a plus sign and a plus sign in any integer operation, the sign will be plus
• If we have a plus sign and a minus sign in multiplication or division, the sign will be minus
• If we have a minus sign and a plus sign in multiplication or division, the sign will be minus
• If we have a minus sign and a minus sign in multiplication or division, the sign will be plus
• If we have a plus sign and a minus sign in addition then we will subtract the values and sign will be of the value which is higher
• If we have a minus sign and a plus sign in addition then we will subtract the values and sign will be of the value which is higher

• If we are asked to subtract then we will change the sign of the second value and follow addition operations,  below are few examples 
      Example: Subtract -2 and -3
      Soln. -2 - (-3)
          = -2 + 3
          = 1
      Example : Subtract -2 and 3
      Soln. -2 - (+3)
          = -2 - 3
          = - 5
      Example : Subtract -2 from 3
      When we have from then the interchange the positions of the values
      Soln. 3 - (-2)
          = 3 + 2
          = 5