# 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 1Properties of Addition and Subtraction of Integers.**

CBSE Class 7 Mathematics /Integers – Chapter 1

Properties of Addition and Subtraction of Integers.

- Closure under Addition:

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. - 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. - Commutative Property:

Addition is commutative for integers.

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 - Associative property:

Addition is associative for integers.

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. - Additive Identity:

For any integer a, a + 0 = a = 0 + a

Zero is an additive identity for integers.

Important Questions for Practice:

- Write a pair of integers whose sum gives

a) a negative integer

b) zero - Write down a pair of integers whose

a) sum is -5

b) difference is -8

c) sum is zero - Write a negative integer and a positive integer whose difference is -3
- 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)] - Write the properties used here:

a) (-5) + (-2) = (-2) + (-5)

b) [(-1) + (-2)] + (-3) = (-1) + [(-2) + (-3)]

ANSWERS:

- a) (-2) and (-1)

b) 5 and (-5) - a) (-3) and (-2)

b) (-2) and 6

c) 10 and (-10) - (-1) and 2 because (-1) – (2) = (-1) + (-2) = (-3)
- a) (-9) + (-3) = (-3) + (-9)

b) (-25) + 0 = (-25)

c) 13 + (-13) = 0

d) [(-7) + (-8)] + (-2) = (-7) + [(-8) + (-2)] - a) Commutative property

b) Associative property