Class 6 Maths Exercise 4.2 – Integers | Complete Solutions Sindh Textbook
Unit 4: Integers
Exercise 4.2
In this exercise, we solve addition questions involving positive and negative integers. A number line can help us understand integer addition:
- Move right for positive integers.
- Move left for negative integers.
Question 1: Find the Sum Using Number Line
(i) (+2) + (+7)
Starting from +2, move 7 steps to the right.
[
(+2)+(+7)=+9
]
Answer: +9
(ii) (−5) + (−6)
Starting from −5, move 6 steps to the left.
[
(-5)+(-6)=-11
]
Answer: −11
(iii) (+7) + (−4)
Starting from +7, move 4 steps to the left.
[
(+7)+(-4)=+3
]
Answer: +3
(iv) (−8) + (+2)
Starting from −8, move 2 steps to the right.
[
(-8)+(+2)=-6
]
Answer: −6
(v) (+5) + (−8)
Starting from +5, move 8 steps to the left.
[
(+5)+(-8)=-3
]
Answer: −3
(vi) (+9) + (−9)
Starting from +9, move 9 steps to the left.
[
(+9)+(-9)=0
]
Answer: 0
Question 2: Find the Sum Using Number Line
(i) (+5) + (+2) + (+3)
First:
[
(+5)+(+2)=+7
]
Now add +3:
[
+7+(+3)=+10
]
Therefore,
[
(+5)+(+2)+(+3)=+10
]
Answer: +10
(ii) (−5) + (−3) + (−4)
[
(-5)+(-3)=-8
]
[
-8+(-4)=-12
]
Therefore,
[
(-5)+(-3)+(-4)=-12
]
Answer: −12
(iii) (+4) + (+5) + (+1)
[
(+4)+(+5)=+9
]
[
+9+(+1)=+10
]
Therefore,
[
(+4)+(+5)+(+1)=+10
]
Answer: +10
(iv) (−2) + (−6) + (−5)
[
(-2)+(-6)=-8
]
[
-8+(-5)=-13
]
Therefore,
[
(-2)+(-6)+(-5)=-13
]
Answer: −13
Question 3: Solve the Following
(i) (+10) + (+20)
[
(+10)+(+20)=+30
]
Answer: +30
(ii) (−15) + (−25)
[
(-15)+(-25)=-40
]
Answer: −40
(iii) (−20) + (−7)
[
(-20)+(-7)=-27
]
Answer: −27
(iv) (+5) + (−14)
[
(+5)+(-14)=-9
]
Answer: −9
(v) (−14) + (+8)
[
(-14)+(+8)=-6
]
Answer: −6
(vi) (−30) + (+30)
A number and its opposite have a sum of zero.
[
(-30)+(+30)=0
]
Answer: 0
Final Answers at a Glance
Question 1
- (i) +9
- (ii) −11
- (iii) +3
- (iv) −6
- (v) −3
- (vi) 0
Question 2
- (i) +10
- (ii) −12
- (iii) +10
- (iv) −13
Question 3
- (i) +30
- (ii) −40
- (iii) −27
- (iv) −9
- (v) −6
- (vi) 0
Conclusion
This exercise teaches us how to add positive and negative integers. Remember:
- Positive + Positive = Positive
- Negative + Negative = Negative
- When adding a positive and a negative integer, subtract the smaller number from the larger number and use the sign of the number with the greater absolute value.
- A number and its opposite always have a sum of zero.
Example:
[
(+9)+(-9)=0
]
This rule will help Class 6 students solve integer addition questions easily.