Question 1.Write down a pair of integers whose:
(a) sum is -7
(b) difference is -10
(c) sum is 0.
Solution:
(a) Let
us take a pair of integers -3 and -4.
∴ (-3) + (-4) = -3 – 4 = -7
(b) Let
us take a pair of integers -12 and -2
∴ (-12) – (-2) = -12 + 2 =
-10
(c) Let
us take a pair of integers -3 and 3
∴ (-3) + (3) = -3 + 3 = 0
Question 2.
(a) Write a pair of negative integers whose difference gives 8.
(b) Write a negative integer and positive integer whose sum is
-5.
(c) Write a negative integer and a positive integer whose
difference is -3.
Solution:
(a) Let
us have -2 and -10
∴ Difference = (-2) – (-10)
= -2 + 10 = 8
(b) Let
us have -7 and 2
∴ (-7) + (2) = -7 + 2 = -5
(c) Let
us have -2 and 1
∴ (-2) – (1) = – 2 – 1 = -3
Question 3.In a quiz, team A scored -40, 10, 0 and team B scored
10, 0, -40 in three successive rounds. Which team scored more? Can you say that
we can add integers in any order?
table
Solution:Total score of team
A = (-40)
+ (10) + (0) – -40 + 10 + 0 = -30
Total
score of team
B = 10 +
0 + (-40) = 10 + 0 – 40 – -30
∴ The scores of both the
teams are same i.e. -30.
Yes, we
can add the integers in any order.
Question 4.Fill in the blanks to make the following statements
true:
(i) -5 + (-8) – (-8) + (-5) [Commutative
law of additions]
(ii) -53
+ 0 = -53 [Additive Identity]
[Adding 0
to any integer, it gives the same value]
(iii) 17
+ (-17) = 0 [Additive inverse]
(iv) [13
+ (-12)] + (-7) =13 + [(-12) + (-7)] [Associative law of addition]
(v) (-4)
+ [15 + (-3)] – [-4 + 15] + (-3) [Associative law of addition]
Question 1.A book exhibition was held for four days in a school. The number of tickets sold at the counter on the first, second, third and final day was respectively 1094, 1812, 2050 and 2751. Find the total number of tickets sold on all the four days.
Solution:
Number of tickets sold on the
first day = 1094
Number of tickets sold on the
second day = 1812
Number of tickets sold on the
third day = 2050
Number of tickets sold on the
final day = 2751
∴
Total number of tickets sold on all the four days = 1094 + 1812 + 2050 +
2751 = 7,707.
Question 2.Shekhar is a famous cricket player. He has so far scored 6980 runs in test matches. He wishes to complete 10,000 runs. How many more runs does he need?
Solution:
Shekhar has so far scored
6980 runs
He wishes to complete 10,000
runs.
Therefore total number of
runs needed by him = 10,000 – 6980 = 3020 runs
Question 3.In an election, the successful candidate registered 5,77,500 votes and his nearest rival secured 3,48,700 votes. By what margin did the successful candidate win the election?
Solution:
Number of votes secured by
the successful candidate = 5,77,500
Number of votes secured by
his nearest rival = 3,48,700
Therefore, margin of votes to
win the election = 5,77,500 – 3,48,700 = 2,28,800
Question 4.Kirti bookstore sold books worth ₹2,85,891 in the first week of June and books worth ₹4,00,768 in the second week of the month. How much was the sale for the two weeks together? In which week was the sale greater and by how much?
Solution:
Books sold in first week of
June worth ₹2,85,891
Books sold in second week of
the month worth ₹4,00,768
Therefore, total sale of
books in the two weeks together
= ₹2,85,891
+ ₹4,00,768 = ₹6,86,659
In the second week of the
month, the sale of books was greater.
Difference of the sale of
books
= ₹4,00,768
– ₹2,85,891 = ₹1,14,877
Hence, in second week of june, the
sale of books was more by ₹1,14,877.
