Let’s take a moment to overview integers:
➢ Just Imagine you are playing a game where you can win or lose
points.
➢ If you win, you get +5 or +10 points. But if you lose a game, you
lose your points likes -5 or -10.
➢ These numbers, both positive and negative are called Integers.
➢ They help us to keep track of gains and losses in real life, just like
in the game!
➢ It is a key idea in mathematics, integers are the collection of entire
numbers that can be zero, positive, or negative.
➢ They are represented by the letter Z, which is derived from the
German word “Zahlen,” which means “number”.

Example for Integer: lets consider a set of integers which is represented as Z
Z= {…,-3,-3,-1,0,1,2,3,…}

Zero: Zero (0) is neutral; it is neither positive nor negative.

Positive Integers: Z= {1, 2, 3, …}

Negative Integers: Z= {-1, -2, -3 ,…}

1)Closure under Addition:

  • For any two integers a and b, a + b is an integers.
    Let us see whether this property is true for integers or not.
    Statement Observation
    (i) 17 + 23 = 40 ___
    (ii) (-10) + 3 = -7 ___
    (iii) (-20) + 0 = _ ____
    (iv) 3 + (-5) = -2 ___

2)Closure under Subtraction:

  • For any two integers a and b, a – b is an integers.
    What happens when we subtract an integer from another integer? Can we
    say that their difference is also an integer?
    Statement Observation
    (i) 7 – 9 = -2 ____
    (ii) (-10) – (-3) = 7 ____
    (iii) 17 – (-21) = _ _____
    (iv) 3 – (-5) = -2 _____

3)Commutative Property:

  • For ant two integers a and b, we can say a + b = b + a
    We know that 3 + 5 = 5 + 3 = 8, addition is commutative for whole numbers.
    We have 5 + (-6) = -1 and (-6) + 5 = -1
    So, 5 + (-6) = (-6) + 5
    Are the following equal?
    (i) (-8) + (-9) and (-9) + (-8)
    (ii) (-45) + 0 and 0 + (-45)
    And also we know that subtraction is not commutative for whole numbers.
    Consider an integers 5 and (-3).
    Is 5 – (-3) the same as (-3) – 5? No, Because 5 – (-3) = 8 and (-3) – 5 = -8.

4)Associative Property:

  • In general, for ant two integers a and b, we can say a + (b + c) = (a + b) +c
    Consider the integers 3, 2 and 5.
    Look at 3 + (2 + 5) and (3 + 2) + 5 are equal?
    Answer:
    Yes, In both cases we get 10.
    3 + (2 + 5) = 10 and (3 + 2) + 5 = 10.
    Similarly consider -3, 1 and -7.
    (-3) + [1 +(-7)] = -3 + _ =
    [(-3) + 1] + (-7) = -2 + =_
    Is (-3) + [1 +(-7)] same as [(-3) + 1] + (-7) ?

5)Additive Identity:

  • 0 is the additive identity, (a + 0 = a).
    Observe the following and fill in the blanks:
    (i) (-8) + 0 = -8
    (ii) (-23) + 0 = _ (iii) 0 + (-59) = _
    (iv) -61 + _ = -61 (v) 0 + _ = -37
    (vi) _ + 0 = _

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