Questions with Answers, Solution | Number System | Term 1 Chapter 1 | 7th Maths - Exercise 1.4 (Division of Integers) | 7th Maths : Term 1 Unit 1 : Number System
Chapter: 7th Maths : Term 1 Unit 1 : Number System
Exercise 1.4 (Division of Integers)
Exercise 1.4
1. Fill in the blanks.
(i) ( −40) ÷ –1 = 40
(ii) 25 ÷ –5 = −5
(iii) –36 ÷ ( −4) = 9
(iv) (−62) ÷ (−62) =
2. Say true or false.
(i) ( −30) ÷ ( −6) = −6
(–30) ÷ (–6) = 5
(ii) (−64) ÷ (−64)is 0
(–64) ÷ (–64) = 1
3. Find the values of the following.
(i) (−75)÷ 5
(ii) (−100)÷ (−20)
(iii) 45 ÷ (−9)
(iv) (−82)÷ 82
4. The product of two integers is −135. If one number is −15, Find the other integer.
The product of two integers = –135
One number = –15 ,
The other integer = 135 ÷ (–15) = 9
The other integer = 9
5. In 8 hours duration, with uniform decrease in temperature, the temperature dropped 24°. How many degrees did the temperature drop each hour?
The temperature dropped in 8 hours = 24°
The temperature dropped each hour = 24° ÷ 8 = 3°
The temperature dropped 3°C per hour
6. An elevator descends into a mine shaft at the rate of 5 m/min. If the descent starts from 15 m above the ground level, how long will it take to reach –250 m?
The length the elevator descend = 15 m + 250 m = 265 m
Time taken to descend 5 m = 1 minute
Time taken to descend 265 m = 265 ÷ 5 = 53 minutes
It takes 53 minutes to reach – 250 m from 15 m above the ground level.
7. A person lost 4800 calories in 30 days. If the calory loss is uniform, calculate the loss of calory per day.
Lost of calories in 30 days = 4800
Loss of calories in 1 day = 4800 ÷ 30 = 160
Loss of calories per day = 160 calories
8. Given 168 × 32 = 5376 then, find ( −5376) ÷ ( −32) .
168 × 32 = 5376 then (–5376) ÷ (–32) = 168
9. How many ( − ) ’s are there in ( −20) ?
Answer: 5
10. ( −400)divided into 10 equal parts gives _____.
(–400) divided into 10 equal parts gives –40.
Objective type questions
11. Which of the following does not represent an Integer?
(i) 0 ÷ ( −7)
(ii) 20 ÷ ( −4)
(iii) ( −9) ÷ 3
(iv) (12) ÷ 5
Answer : (iv) (12) ÷ 5
12. Which of the following is true?
(i) (–5) > (6)
(ii) (6) > (5)
(iii) (–6) > 5
(iv) (–5) > 6
Answer : (i) (–5) > (6)
13. ( −16) ÷ 4 is the same as
(i) −(−16 ÷ 4)
(ii) −(16) ÷ (−4)
(iii) 16 ÷ ( −4)
(iv) −4 ÷16
Answer : (iii) 16 ÷ (–4)
14. ( −200) ÷10 is
(i) 20
(ii) −20
(iii) −190
(iv) 210
Answer : (ii) –20
15. The set of integers is not closed under
(i) Addition
(ii) Subtraction
(iii) Multiplication
(iv) Division
Answer : (iv) Division
Do you know
One of the earliest exposition on negative numbers is by the 7th century Indian Mathematician and Astronomen Brahma gupta, who in his famous text “Brahmasphutasuddhanta” gave a very clear understanding of the concept of zero and consequently the negative integers. His texts were in the form of poetry which when translated reads something like this…
Rule for dealing with positive (fortune) and negative (debt) numbers.
● A debt minus zero is a debt
● A fortune minus zero is a fortune.
● Zero minus zero is a zero.
● A debt subtracted from zero is a fortune.
● A fortune subtracted from zero is a debt.
● The Product of zero by a debt or fortune is zero.
● The Product of zero by zero is zero.
● The Product of quotient of two fortunes is one fortune.
● The Product of quotient of a debt and a fortune is a debt.
● The Product or quotient of a fortune and a debt is a debt.
- The story of mathematics
ANSWERS
Exercise 1.4
1. (i) −1 (ii) −5 (iii) −36 (iv) 1
2. (i) False (ii) False
3. (i) −15 (ii) 5 (iii) −5 (iv) −1
4. 9
5. dropped 3˚c per hour
6. 53 minutes
7. 160 calories lost per day
8. 168
9. 5
10. −40
Objective type questions
11. (iv) 12 ÷ 5
12. (iii) 16 ÷ ( −4)
13. (ii) – 20
14. (iv) division
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