S Chand ICSE Mathematics Class 6 Solution Third Chapter Negative Numbers and Integers Exercise 3B (O.P. Malhotra,  S.K. Gupta, Anubhuti Gangal)

EXERCISE 3B

(1) Write the addition sentences shown by the following number lines.

(i) – 3 + 5 = 2

(ii) 9 + (- 2) = 7

(iii) (- 2) + (- 4) = – 6

(iv) – 5 + 13 = 8

(v) – 4 + 4 = 0

(2) Use the number line and add the following integers.

(3) Add without using the number line.

(i) – 8 + (- 4) = – 12

(ii) 5 + (- 4) = 1

(iii) – 17 + 24 = 7

(iv) 0 + (- 36) = – 36

(v) 27 + (- 27) = 0

(vi) – 692 + 258 = – 434

(vii) 4004 + (- 999) = 3005

(viii) – 1530 + 0 = – 1530

(ix) 5987 + (- 5987) = 0

(x) 3958 + (- 3959) = – 1

(xi) – 712 + 2538 + 712

= – 712 + 712 + 2538

= 2538

(xii) – 729 + (- 7098) + 729

= – 729 + 729 – 7098

= 7098

(4) – 7 + 10 = 3 km

Ans: 3 km high above the sea level is the tip of the iceberg.

(5) – 10 + 5 – 4 – 3 + 15

= – 10 – 4 – 3 + 5 + 15

= – 17 + 20

= 3

The final score is +3.

(6) Find the sum.

(i) 200 + (- 55) + (- 77) + (- 68)

= 200 – 55 – 77 – 68

= 200 – 200

= 0

(ii) 1393 + (- 407) + (- 872) + 690

= 1393 + 690 – 407 – 872

= 2083 – 1279

= 804

(iii) 703 + (- 3) + (- 1) + 1 + (- 400) + 0

= 703 + 1 – 3 – 1 – 400

= 704 – 404

= 300

(iv) 2000 + 516 + (- 517) – 1999

= 2516 – 2516

= 0

(7) Write the addition sentence corresponding to each of the following subtraction sentences.

(i) 1 + (- 8)

(ii) – 8 + (- 11)

(iii) 4 + 3

(iv) – 9 + 12

(v) – 10 + 7

(8) Find:

(i) 5 – 9 = – 4

(ii) 2 – (- 7)

= 2 + 7 = 9

(iii) – 11 – (- 9)

= – 11 + 9 = – 2

(iv) – 9 – (- 12)

= – 9 + 12 = 3

(v) 0 – 75 = – 75

(vi) 0 – (- 45) = 45

(9) Write the successor and predecessor of each of the following.

(i) 6, 4

(ii) – 2, – 4

(iii) – 99, – 101

(iv) 1, – 1

(10) Subtract the first integer from the second in each of the following.

(i) – 2 – 8 = – 10

(ii) – 12 – (- 15)

= – 12 + 15 = 3

(iii) 307 – (- 93)

= 307 + 93

= 400

(iv) 0 – (- 267)= 267

(v) 7003 – 0 = 7003

(vi) – 45632 – (- 35632)

= – 45632 + 35632

= – 10000

(11) Find the value of:

(i) – 8 – (- 15) – 10

= – 8 – 10 + 15

= – 18 + 15 = – 3

(ii) 6 – 7 – (- 23)

= 6 + 23 – 7

= 29 – 7 = 22

(iii) (3 – 4) + (3 – 4)

= – 1 – 1 = – 2

(iv) – 60 – (- 58) – (- 2)

= – 60 + 58 + 2

= – 60 + 60 = 0

(12) Fill in the blanks by <, > or = to make each sentence true.

(i) (- 3) + (- 7) < (- 3) – (- 7)

= (- 3 – 7) < (- 3 + 7)

= – 10 < + 4

(ii) (- 23) – (- 23) > (- 23) + (- 23)

= (- 23 + 23) > (- 23 – 23)

= 0 > – 46

(iii) – (30) – 30 < – 30 + 30

= (- 30 – 30) < (- 30 + 30)

= – 60 < 0

(iv) (- 15) + (- 25) = (- 25) – 15

= (- 15 – 25) = (-25 – 15)

= – 45 = – 45

(13) The difference between the inside and outside temperature is

= – 10o – (- 35)o

= – 10o + 35o

= 25o C

(14) The maximum temperature than the minimum temperature is

= 130o – (- 110o)

= 130o + 110o = 140o C

(15) Subtract the sum of

(i) – 45 – (- 340 + 170)

= – 45 + 340 – 170

= – 215 + 340 = 125

(ii) (- 385 – 675) – {865 + (- 493)}

= – 1060 – 865 + 493

= – 1925 + 493 = – 1432

Multiple choice Questions (MCQs)

(16) (b) – 250 + (- 75)

(17) (c) – 10 + 8

(18) (c) The sum of two negative integers is a negative integer.

(19) (c) – 53 + 72

(20) (b) 4 – (- 1)

(21) (a) 2754

(22) 45 – 23 = (b) 22

(23) Answer True (T) or False (F).

(i) T

(ii) F

(iii) F

(iv) F

(24) (d) – 1.