Selina Concise Class 6 Math Chapter 5 Natural Numbers and Whole Numbers Exercise 5(C) Solution:
(1) Fill in the blanks:
(i) 42 x 0 = 0
(ii) 592 x 1 = 592
(iii) 229 x ____ = 578 x 229
Ans. 578
(iv) 229 x _____ = 578 x 229
Ans. 578
(v) 32 x 15 = 32 x 6 + 32 x 7 + 32 x _____
Ans. 2
(vi) 23 x 56 = 20 x 56 + ____ x 56
Ans. 3
(vii) 83 x 54 + 83 x 16 = 83 x _______ = 83 x ____ = ______
Ans. (54 + 16), 70, 5810
(viii) 98 x 273 – 75 x 273 = _______ x 273 = ______ x 273
Ans. 98, 23.
(2) By rearranging the given numbers, evaluate:
(i) 2 x 487 x 50
= (2 x 487) x 50
= 974 x 50
= 48700
(ii) 25 x 444 x 4
= (25 x 444) x 4
= 11100 x 4
= 44400
(iii) 225 x 20 x 50 x 4
= (225 x 20) x (50 x 4)
= 4500 x 200
= 900000
(3) Use distributive law to evaluate:
(i) 984 x 102
= (900 + 80 + 4) x 102
= 900 x 102 + 80 x 102 + 4 x 102
= 91800 + 8160 + 408
= 100368
(ii) 385 x 1004
= (300 + 80 + 5) x 1004
= 300 x 1004 + 80 x 1004 + 5 x 1004
= 301200 + 80320 + 5020
= 386540
(iii) 446 x 10002
= (400 + 40 + 6) x 10002
= 400 x 10002 + 40 x 10002 + 6 x 10002
= 4000800 + 400080 + 60012
= 4460892
(4) Evaluate using properties:
(i) 548 x 98
= (500 + 40 + 8) x 98
= 500 x 8 + 40 x 98 + 8 x 98
= 4000 + 3920 + 784
= 8704
(ii) 924 x 988
= (900 + 20 + 4) x 988
= 900 x 988 + 20 x 988 + 4 x 988
= 889200 + 19760 + 3952
= 912912
(iii) 3023 x 723
= (3000 + 000 + 20 + 3) x 723
= 3000 x 723 + 000 x 723 + 20 x 723 + 3 x 723
= 2169000 + 000 + 14460 + 2169
= 2185629
(5) Evaluate using properties:
(i) 679 x 8 + 679 x 2
= 679 x (8+2)
= 679 x 10
=6790
(ii) 284 x 12 – 284 x 2
= 284 x (12 – 2)
= 284 x 10
= 2840
(iii) 55873 x 94 + 55873 x 6
= 55873 x (94 +6)
= 55873 x 100
= 5587300
(iv) 7984 x 15 – 7984 x 5
= 7984 x (15 -5)
= 7984 x 10
= 79840
(v) 8324 x 1945 – 8324 x 945
= 8324 x (1945 – 945)
= 8324 x 1000
= 8324000
(vi) 3333 x 987 + 13 x 3333
= 3333 x(987 + 13)
= 3333 x 1000
= 3333000
(6) Find the product of the :
(i) greatest number of three digits and smallest number of five digits.
Solution: 999 x 10000 = 9990000
(ii) greatest number of four digits and the greatest number of three digits.
Solution: 9999 x 999 = 9989001
(7) Fill in the blanks:
(i) (437 + 3) x (400 – 3) = 397 x ______
Ans. 440
(ii) 66 + 44 + 22 = 11 x _______ = 11 x ___
Ans. (6 + 4 + 2) = 11 x 12
(8) Evaluate:
(i) 355 x 18
= (300 + 50 + 8) x 18
= 300 x 18 + 50 x 18 + 8 x 18
= 5400 + 900 + 144
= 6444
(ii) 6214 x 12
= (6000 + 200 + 10 + 4) x 12
= 6000 x 12 + 200 x 12 + 10 x 12 + 4 x 12
= 72000 + 2400 + 120 + 48
= 74568
(iii) 15 x 49372
= (10 + 5) x 49372
= 10 x 49372 + 5 x 49372
= 493720 + 246860
= 740580
(iv) 9999 x 8
= (9000 + 900 + 90 + 9) x 8
= 9000 x 8 + 900 x 8 + 90 x 8 + 9 x 8
= 72000 + 7200 + 720 + 72
= 79992
good