ML Aggarwal Class 7 Solutions for ICSE Maths Chapter 1 Integers Ex 1.1
Question 1.
Some integers are marked on the following number line:
(i) Write these integers in ascending order.
(ii) Write these integers in descending order.
(iii) Few dots have been marked on the above number line. Write an appropriate integer at each dot.
Solution:
(i) -18, -9, -4, 0, 3, 8, 12
(ii) 12, 8, 3, 0, -4, -9, -18
(iii) Integer from left to right are -17, -14, -11, -7, -5, -3, 1, 4, 7, 9, 11
Question 2.
A number line representing integers is given below:
The integers -3 and -2 are marked by points E and F respectively. Which integers are marked by points B, D, H, J, M and O?
Solution:
The integers which marked by the points B, G, H, J, M and O are respectively -6, -1, 0, 2, 5, 7
Question 3.
Arrange 7, -5, 4, 0 and -4 in ascending order and mark them on a number line to check your answer.
Solution:
Arranging the given integers in ascending order, -5, -4, 0, 4, 7 and marked on the number line is given below:
Question 4.
In a quiz, positive marks are given for correct answers and negative marks are given for incorrect answers. If Rohit’s scores in five successive rounds were 15, -3, -7, 12 and 8, what was his total at the end?
Solution:
Rohit’s scores in 5 successive rounds, were 15, -3, -7, 12, 8
His total score will be = 15 – 3 – 7 + 12 + 8 = 15 + 12 + 8 – 3 – 7 = 35 – 10 = 25
Question 5.
Ruchi deposited ₹ 4370 in her account on Monday and then withdrew ₹ 2875 on Tuesday. Next day she deposited ₹ 1550. What was her balance on Thursday?
Solution:
Ruchi deposited ₹ 4370 on Monday ₹ 1550 on Wednesday.
So, her total deposit = ₹ 4370 + ₹ 1550 = ₹ 5920
and withdraw = ₹ 2875
Balance on Thursday = ₹ 5920 – ₹ 2875 = ₹ 3045
Question 6.
Ravi goes 28 km towards east from a point P to the point Q. From Q, he moves 37 km towards the 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 the west? By which integer will you represent his final position from P?
Solution:
From point P to Q, Ravi goes 28 km towards East.
From Q to the West, 37 km
So, +28 – 37 = -9 km to the West, he will be
His final position will be -9 km from P.
Question 7.
Fill in the blank spaces by integers of the given magic square so that the sum of the integers in each row, each column and each diagonal is -6.
Solution:
Sum of integers of the magic square is -6 in each row, column and each diagonal as shown here:
Question 8.
Evaluate the following:
(i) |-13| – |9|
(ii) |13 – 5| – |-9|
(iii) |35 – 21| – |8 – 3|
Solution:
(i) |-13| – |9| = 13 – 9 = 4
(ii) |13 – 5| – |-9| = |8| – |-9| = 8 – 9 = -1
(iii) |35 – 21| – |8 – 3| = |14| – |5| = 14 – 5 = 9
Question 9.
Arrange the following integers in ascending order:
-39, 35, -102, 0, -51, -5, -6, 7
Solution:
-39, 35, -102, 0, -51, -5, -6, 7
Arranging in ascending order:
-102, -51, -39, -6, -5, 0, 7, 35
Question 10.
Arrange the following integers in descending order:
-31, 139, -203, -97, 0, 4208
Solution:
-31, 139, -203, -97, 0, 4208
Arranging in descending order,
4208, 139, 0, -31, -97, -203
Question 11.
State whether each of the following statement is true or false:
(i) 0 is the successor of -1 in integers
(ii) 0 has no predecessor in integers
(iii) -2 is the predecessor of -1
(iv) 0 is greater than every negative integer.
Solution:
(i) 0 is the successor of -1 integer: True
(ii) 0 has no predecessor in integers: False
As 0 has -1 as its predecessor.
(iii) -2 is the predecessor of -1: True
(iv) 0 is greater than every negative integer: True
Question 12.
Use the sign >, < or = in the box to make the following statements true:
(i) (-11) + (-7) ……….. (-11) – (-7)
(ii) 23 – 41 + 11 ……… 23 – 41 – 11
(iii) 40 – (-39) + (-5) …….. 40 + (-39) – (-5)
(iv) (-3) + 13 – (15) ……. 25 – (-2) + (-33)
Solution:
(i) (-11) + (-7) …… (-11) – (-7)
⇒ -18 < -11 + 7 = -4
(ii) 23 – 41 + 11 ….. 23 – 41 – 11
⇒ 34 – 41 ……. 23 – 52
⇒ -9 > -19
(iii) 40 – (-39) + (-5) …… 40 + (-39) – (-5)
⇒ 40 + 39 – 5 …… 40 – 39 + 5
⇒ 79 – 5 …… 45 – 39
⇒ 74 > 6
(iv) (-3) + 13 – (15) …….. 25 – (-2) + (-33)
⇒ -3 + 13 – ……. 25 + 2 – 33
⇒ 13 – 18 ……. 27 – 33
⇒ -5 > -6