Selina Concise Class 6 Math Chapter 5 Natural Numbers And Whole Numbers Exercise 5(A) Solution

Selina Concise Class 6 Math Chapter 5 Natural Numbers And Whole Numbers Exercise 5(A) Solution:

(1) Fill in the blanks:

(i) 1

(ii) 0

(iii) not possible

(iv) not possible

(v) Whole number

(vi) natural number

(vii) 4099 + 1 = 4100

(viii) 4330 – 1 = 4329

(2) Represent the following whole numbers on a number line:

0, 3, 5, 8, 10

Solution:

(3) State True or false

(i) Whole number are closed for addition – True

(ii) If a and b are any two whole numbers, Then a + b is not a whole number. – False

(iii) If a and b are any two whole numbers, then a + b = b + a. – True

(iv) 0 + 18 = 18 + 0. – True

(v) Addition of whole numbers is associative. – True

(vi) 10 + 12 + 16 = (10 + 12) + 16 = 10 + (12 + 16). – True.

(4) Fill in the blanks:

(i) 54 + 234 = 234 + _____

Ans. 54.

(ii) 332 + 497 = ______ + 332

Ans. 497.

(iii) 286 + 0 = ______

Ans. 286

(iv) 286 x 1 = ______

Ans. 286

(v) a + (b + c) = (a + ____) + c

Ans. a

(5) By re-arranging the given numbers, evaluate

(i) 237+ 308 = 234 + ____

Ans. 308

(ii) 162 + 253 + 338 + 47

Solution: (162 + 253) + (338 + 47)

= 415 + 385

= 800

(iii) 21 + 22 + 23 + 24 + 25 + 75 + 76 + 77 + 78 + 79

Solution: (21 + 75) + (22 + 76) + (23 + 77) + (24 + 78) + (25 + 79)

= 96 + 98 + 100 + 102 + 104

= 500

(iv) 1 + 2 + 3 + 4 + 596 + 597 + 598 + 599

Solution: (1 + 596) + (2 + 597) + (3 + 598) + (4 + 599)

= 597 + 599 + 601 + 603

= 2400

(6) Is a + b + c = a + (b + c)

= (b + a) + c?

Ans. Yes, It is true.

(7) Which property of addition is satisfied by :

(i) 8 + 7 = 15 = Closure property

(ii) 3 + (5 + 4) = (3 + 5) + 4 = Associative property.

(iii) 8 x (8 + 0) = 8 x 8 + 8 x 0 = Distributive property.

(iv) (7 + 6) x 10 = 7 x 10 + 6 x 10 = Distributive property

(v) (15 – 12) x 18 = 15 x 18 – 12 x 18 = Distributive property

(vi) 16 + 0 = 16 = Existence of Identity

(vii) 23 + (-23) = 0 Additive inverse.

(8) State true or False.

(i) The sum of two odd numbers is odd numbers. (False)

(ii) The sum of two odd numbers is an  even number. (True)

(iii) The sum of two even numbers is an even number. (True)

(iv) The sum of two even numbers is an odd number. (False)

(v) The sum of an even number and an odd number is odd number. (True)

(vi) Every whole number is a natural number. (True)

(vii) Every natural number is a whole number. (True)

(viii) Every whole number + 0 = The whole number itself. (False)

(ix) Every whole number x 1 = The whole number itself. (true)

(x) Commutativity and Associativity are properties of natural numbers and whole numbers both. (False)

(xi) Commutativity and associativity are properties of addition for natural numbers and whole numbers both. (True)

(xii) If x is a whole number then –x is also a whole number. (False)

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