In this section of NCERT Maths Solution for Class 7 Chapter Integers, Detailed solution of all questions are provided. By practicing the question the student can get good marks in their exam/test.
We know that the collection of whole number and negative numbers, is called Integers
Whole Numbers-
All natural numbers with zero, is called whole numbers.
i.e. 0, 1, 2, 3, 4, 5 ……..
Negative Numbers-
i.e. -1, -2, -3, -4, -5 ……..
Additive Inverse-
Additive inverse of an integers (a) is (-a) and additive inverse of (-a) is (a).
i.e.
e. Integers Additive Inverse
5 -5
-2 2
-4 4
6 -6
Question 1:
Fallowing numbers line shows the temperature in degree Celsius (0 C) at different places on a particular day.
(a)
Observe this number line and write the temperature of the places marked on it.
Temperature of Lahulspiti = -80 C
Temperature of Srinagar = -20 C
Temperature of Shimla = -50C
Temperature of Oaty = -140C
Temperature of Bangalore = -220
(b)
What is the temperature between the hottest and the coldest places among the above?
Hottest place is Bangalore and coldest place is Lahulspiti
220C – (-80C) = 300C
What is the temperature between the hottest and the coldest places among the above?
Hottest place is Bangalore and coldest place is Lahulspiti
220C – (-80C) = 300C
(c)
What is the temperature difference between Lahulspiti and Srinagar?
Temperature of Lahulspiti is -80C and Temperature of Srinagar is -20C
= -20C – (-80C)
= -20C + 80C
= 60C
(d)
Can we say temperature of Srinagar and Shimla taken together is less than the temperature at Shimla? It is also less than the temperature at Srinagar.
Yes, No
Question 2:
In a quiz positive marks are given for correct answer and negative marks are given for incorrect answers.
If Jack scores in five successive rounds were 25,-5,-10, 15, and10
What was the total at the end?
Jack’s total marks =25 + (-5) + (-10) + 15 + 10
= 35
Question 3:
At Srinagar temperature was -50C on Monday and then it dropped by 20C on Tuesday .What was the temperature of Srinagar on Tuesday? On Wednesday, it rose by 40C what was the temperature on this day?
The temperature of Srinagar on Tuesday = -50C -20C
= – 70C
And temperature on Wednesday is rose by 40C
=-70C+40C
= -30C
Question 4:
A plane is flying at the height of 5000m above the sea level, at a particular point; it is exactly above a submarine floating 1200m below the sea level .What is the vertical distance between the Plane and submarine?
= 5000m – (-1200m) = = 6200m
Question 5:
Mohan deposited Rs.2000 in his bank account and withdraws
Rs.1642 from it, the next day, if withdraws amount from the account is represented by a negative integer, then how will you represent the amount deposited? Find the balance in Mohan’s account after the withdrawal.
I will represent deposited amount by positive Integer.
Balance in Mohan’s account = 2000 – 1642 =358 Rs.
Question 6:
Rita goes 20 Km. towards east from a point A to the point B.From B, she moves 30 Km. towards west along the same road If the distance towards west along the same road.If the distance towards east is represented by a positive integer then how will you represent the distance travelled towards west ? By which integer will you represent her final position from A?
By a negative Integer
Final position represent by = -10
Question 7
In a magic square each row,column and diagonal have the same sum .Check which of fallowing is a magic square?
In square (i) the sum of all row, column and diagonals are zero.
Therefore Option (i) is a magic square.
Question 8
Verify a-(-b) = a+b for the fallowing values of a and b
(A)- a = 21 and b = 18
Putting value in given equation
21-(-18) = 21+18 { since – & – = + }
21+18 = 21+18
39 = 39(B)-
a =118 and b= 125
Putting value in given equation
118-(-125) = 118+125 { since – & – = + }
118+125 = 118+125
243 = 243
(C)-
a =75 and b= 84
Putting value in given equation
75-(-84) = 75+84 { since – & – = + }
75+84 = 75+84
159 = 159
21+18 = 21+18
39 = 39
(B)-
a =118 and b= 125
Putting value in given equation
118-(-125) = 118+125 { since – & – = + }
118+125 = 118+125
243 = 243
(C)-
a =75 and b= 84
Putting value in given equation
75-(-84) = 75+84 { since – & – = + }
75+84 = 75+84
159 = 159
(D)- a =28 and b= 11
Putting value in given equation
28-(-11) = 28+11 { since – & – = + }
28+11 = 28+11
39 = 39
Question 9
Use the sign of >,< and = in the box to makes the statement true.
(a)-
(-8) + (-4) < – (-4)
(b)-
(-3) + 7- (19) [ < ] 15 – 8 +(-9)
(c)-
- 41 + 11 [ > ] 23 – 41 – 23 11
(d)-
39 + (-24) – (15) [ > ] 36 + (-52) – (-36)
(e)-
-231 +79 +51 [ > ] -399+ 159 + 81
Question 10(i)
A water tank has steps inside . A monkey is sitting on the top most step (i.e. the first steps)
The water level is at the ninth step.
(a)-
He jumps 3 steps down and then jump back 2 steps up.In how many jumps will he reach the water level ?
Question 10 (ii)
After drinking water,he wants to go back.For this ,he jumps 4 steps up and then jumps back 2 steps down in every move ,In how many jumps will he reach back the top step?
We take positive sign(+) for up word direction and negative sign for (-) down word direction.
Question 10(iii)
If the number of steps moved down is represent by negative integer and the number of steps moved up is represented by positive integer,represent his move in part (1) and part (2) by completing the fallowing.
(a) -3 + 2- 3+ 2 -3+2 -3+2 -3+2 = -8
(b) 4-2 +4-2 +4-2 +4-2 = 8
Question 10(iv)
The sum (-8) represents going down by eight steps so,what will the sum (8) in (b).
Going up 8 steps
NCERT Class 7 Maths Exercise 1.2 Solution