# CBSE Class 7 Mathematics/Integers

CBSE Class 7 Mathematics/Integers is about the properties of addition and subtraction of integers. Here you can find out practice problems from the chapter Integers.

CBSE Class 7 Mathematics /Integers – Chapter 1
Properties of Addition and Subtraction of Integers.

CBSE Class 7 Mathematics /Integers – Chapter 1
Properties of Addition and Subtraction of Integers.

For any two integers a and b, a + b is an integer.
Since addition of integers gives integers, we say integers are closed under addition.
2. Closure under Subtraction:
If a and b are two integers then a – b is also an integer.
Since subtraction of integers gives integers, we say integers are closed under subtraction.
3. Commutative Property:
For any two integers a and b, a + b = b + a
We have 5 + (-6) = -1 and (-6) + 5 = -1
So 5 + (-6) = (-6) + 5
4. Associative property:
For any integers a, b and c, a + (b + c) = (a + b) + c
Consider the integers -3, -2 and -5
Look at (-5) + [(-3) + (-2)] and [(-5) + (-3)] + (-2)
(-5) + [(-3) + (-2)] = (-5) + (-5) = -10
[(-5) + (-3)] + (-2) = (-8) + (-2) = -10
In both the cases we get -10, so associativity holds.
For any integer a, a + 0 = a = 0 + a
Zero is an additive identity for integers.

Important Questions for Practice:

1. Write a pair of integers whose sum gives
a) a negative integer
b) zero
2. Write down a pair of integers whose
a) sum is -5
b) difference is -8
c) sum is zero
3. Write a negative integer and a positive integer whose difference is -3
4. Fill in the blanks to make the following statements true:
a) (-9) + (-3) = (-3) + —–
b) -25 + ——- = -25
c) 13 + ——– = 0
d) [(-7) + (-8)] + (-2) = —– + [(-8) + (-2)]
5. Write the properties used here:
a) (-5) + (-2) = (-2) + (-5)
b) [(-1) + (-2)] + (-3) = (-1) + [(-2) + (-3)]

1. a) (-2) and (-1)
b) 5 and (-5)
2. a) (-3) and (-2)
b) (-2) and 6
c) 10 and (-10)
3. (-1) and 2 because (-1) – (2) = (-1) + (-2) = (-3)
4. a) (-9) + (-3) = (-3) + (-9)
b) (-25) + 0 = (-25)
c) 13 + (-13) = 0
d) [(-7) + (-8)] + (-2) = (-7) + [(-8) + (-2)]
5. a) Commutative property
b) Associative property