MP Board Class 7 Maths Solutions For Chapter 1 Integers
1. Evaluate each of the following:
1) (-30) ÷ 10
Solution: (-30) ÷ 10 = -3
2) 50 ÷ (-5)
Solution: 50 ÷ (-5) = -10
3) (-36) ÷ (-9)
Solution: (-36) ÷ (-9) =4
4) (-49) ÷ 49
Solution: (-49) ÷ 49 =-1
5) 13 ÷ [(-2) + 1]
Solution: 13 ÷ [(-2) + 1] = 13 ÷ (-1) = -13
6) 0 ÷(-12)
Solution: 0 ÷ (-12) = 0
7) (-31) ÷ [(-30) + (-1)]
Solution: (-31)+ [(-30) +(-1)] = (-31) + (-31) = 1
8) (-36) +12) ÷ 3
Solution: [(-36) +12)] ÷ 3 =(-3) ÷ 3 =-1
Mp Board Class 7 Maths Solutions
9) [(-6) +5] ÷ [(-2)+1]
Solution: [(- 6) + 5]÷ [(-2) +1] = (-1) + (-1) =1
2) Verify that a + (b + c) (a + b) + (a + c) for each of the following values of a, b and c.
1) a = 12 ; b = -4 ; c = 2
Solution: a ÷ (b + c) =12 ÷ [(- 4) + 2]
= 12 ÷ (-2) =- 6
[a ÷ b] +[a ÷ c] =[12 ÷ (- 4)] +[12 ÷ 2]
= (-3) +6 = 3
a ÷ (b ÷ c) ≠ (a ÷ b) + (a ÷ c)
2) a = -10 ; b =1 ; c =1
Solution: a ÷ (b + c) = (-10) ÷ (1 + 1)
= (-10) ÷ 2 = -5
[a ÷ b] + [a ÷ c] = [(-10) +1]
+ [(-10) ÷ 1] = (-10) + (-10) = -20
a ÷ (b + c) ≠ (a ÷ b) + (a ÷ c)
Class 7 Maths Chapter 1 Solutions Mp Board
3. Fill in the blanks:
1) 369 + 1 =369
2) (-75) +75 =-1
3) (-206) + (-206) =1
4) (-87) + (-1) = 87
5) -87 + 1 = -87
7) (-48) + 48 =-1
8) 20 +(-10) = -2
9) (-12) +4 = -3 .
4. Write five pairs of integers (a, b) such that a ÷ b = -3. One such pair is (6, -2) because 6 ÷ (-2) = -3.
Solution:
Five pairs of integers (a, b) such that a ÷ b = -3 are
1) 9 ÷ (-3) =-3 ∴ [9,-3]
2) 12 ÷ (-4) =-3 ∴ [12,-4]
3) 27 ÷ (-9) = -3 ∴ [27,-9]
4) 15÷ (-5)= -3 ∴ [15,-5]
5) (-18) ÷ 6 =-3 ∴ [-18,6]
Mp Board Maths Chapter 1 Solutions
5. The temperature at 12 noon was 10°C above zero.If it decreases at the rate of 2°C. per horn: until midnight, at what time would the temperature be 8°C below zero? What would be the temperature at mid night?
Solution:
Temperature. at 12 noon = 10°C
Temperature at 1 PM = = 10°C- 2°C = 8°C
Temperature at 3 PM = 6°C – 2°C = 4°C
Temperature at 4 PM = 4°C- 2°C = 2°C
Temperature at 5 PM = 2°C- 2°C = 0°C
Temperature at 6 PM = 0°C- 2°C = – 2°C
Temperature at 7PM = -2°C- 2°C =-4°C
Temperature at 8 PM =- 4°C- 2°C =- 6°C
Temperature at 9 PM = – 6°C- 2°C =- 8°C
The temperature will be 8°C below zero at 9 PM
Temperature at 10 PM =- 8°C- 2°C =- 10°C
Temperature at11 PM =- 10°C- 2°C =- 12°C
Temperature at12 PM i.e. midnight = -12°C- 2°C =- 14°C
Temperature at midnight is 14 degrees below zero.
Mp Board Class 7 Book Solutions
6. In a class test (+3) marks are given for every correct answer and (-2) marks are given for every incorrect answer and no marks for not attempting any question.
1) Radhika scored 20 marks. If she has got 12 correct answers, how many questions has she attempted incorrectly ?
2) Mohini scores -5 marks in this test, though she has got 7 correct answers.How many questions has she attempted incorrectly?
Solution:
1) Marks given for each correct answer = 3
Marks given for 12 correct answers =12×3 = 36
Radhika’s score = 20
Marks given for incorrect answers = 20 -36 = -16
Marks given for each incorrect answer = (-2)
So number of incorrect answers = (-16) + (-2) = 8
2) Marks given for 7 correct answers = 7 x 3 = 21
Mohini’s score = -5
Marks received for incorrect answers = -5-21 = -26
Marks given for one incorrect answer = -2
Number of incorrect answers = -26/-2 =13
7. An elevator descends into a mine shaft at the rate of 6 m/min. If the descent starts from 10 m above the ground level, how long will it take to reach – 350 m ?
Solution: Total distance covered by elevator = 10 -(-350) =360m
Speed of the elevator = 6 m / min
360 m descent = -360/6 = 60 min
∴ The elevator will take 60 minutes or 1hour to reach- 350m below the ground level.
1) (-100)÷ 5
Solution: (-100) ÷ 5 = -20
2) (-81) ÷ 9
Solution: (-81) ÷ 9 = -9
3) (-75) ÷ 5
Solution: (-75) ÷ 5 = -15
4) (-32) ÷ 2
Solution: (-32) ÷ 2 = -16
Find
1) 125 ÷ (-25)
Solution: 125 ÷ (-25) = -5
2) 80 ÷ (-5)
Solution: 80÷(-5) = -16
3) 64 ÷(-16)
Solution: 64 +(-16) =- 4
Find
1) (-36) ÷ (-4)
Solution: (-36) ÷ (-4) =9
2) (-201) ÷ (-3)
Solution: (-201) ÷ (-3) =67
3) (-325) ÷ (-13)
Solution: (-325) ÷ (-13) =25
Class 7 Mp Board Maths Question Answers
Solutions To Try These
Is
1) 1 ÷ a = 1 ?
Solution: No,1 ÷ a ≠ 1 unless a =1
2) a ÷ (-1) = -a ? for any integer a. Take different values of a and check.
Solution: Yes, a ÷ (-1) = -a
Examples:
1) Take a = 4
- 1 ÷ 4 ≠ 1
- 4 ÷ (-1) = -4
2) Take a = -5
- 1 ÷ (-5) ≠ 1
- (-5) ÷ (-1) = 5 =-(-5)