The document RD Sharma Solutions -Ex-4.1, Operations On Whole Numbers, Class 6, Maths Class 6 Notes | EduRev is a part of the Class 6 Course RD Sharma Solutions for Class 6 Mathematics.

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**Q. 1. Fill in the blanks to make each of th e following a true statement:**

**Solution:** (i) 359 + 476 = 476 + 359 (Commutativity)

(ii) 2008 + 1952 = 1952 + 2008 (Commutativity)

(iii) 90758 + 0 = 90758 (Additive identity)

(iv) 54321 + (489 + 699) = 489 + (54321 + 699) (Associativity)

**Q. 2. Add each of the following and check by reversing the order of addends:**

**Solution:** (i) 5628 + 39784 = 45412

And,

39784 + 5628 = 45412

(ii) 923584 + 178 = 923762

And,

178 + 923584 = 923762

(iii) 15409 + 112 = 15521

And,

112 + 15409 = 15521

(iv) 2359 + 641 = 3000

And,

641 + 2359 = 3000

**Q. 3. Determine the sum by suitable rearrangements:**

**Solution:** (i) 953 + 407 + 647

Therefore, 53 + 47 = 100

Therefore, (953 + 647) + 407 = 1600 + 407 = 2007

(ii) 15409 + 178 + 591 + 322

409 + 91 = 500

And,

78+22 = 100

Therefore, (15409 + 591) + (178 + 322) = (16000) + (500)

= 16500

(iii) 2359 + 10001 + 2641 + 9999

Therefore, 59 + 41 = 100

And, 99 + 01 = 100

Therefore, (2359 + 2641) + (10001 + 9999)

= (5000) + (20000)

= 25000

(iv) 1 +2+3+4+1996+1997+1998+1999

Therefore, 99 + 1 = 100

98 + 2 = 100

97 + 3 = 100

And

96 + 4 = 100

Therefore, (1 + 1999) + (2 + 1998) + ( 3 + 1997) + (4 + 1996)

= 2000 + 2000 + 2000 + 2000

= 8000

(v) 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20

10 + 20 = 30

1 + 9 = 10

2 + 8 = 10

3 + 7 = 10

And,

4 + 6 = 10

Therefore, (10 + 20) + (11 + 19) + (12 + 18) + (13 + 17) + (14 + 16)

= 30 + 30 + 30 + 30 + 30 + 15

= 150 + 15

= 165

**Q. 4. Which of the following statements are true and which are false?**

**(i) The sum of two odd numbers is an odd number.**

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

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

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

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

**(vi)The sum of an odd number and an even number is an even number.**

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

**(viii) Every natural number is a whole number.**

**(ix) There is a whole number which when added to a whole number, gives that number**

**(x) there is a natural number which when added to a natural number, gives that number.**

**(xi) commmutativity and associativity are properties of whole numbers.**

**(xii) commmutativity and associativity are properties of addition of whole number.**

**Solution:** (i) FALSE (3 + 5 = 8; 8 is an even number)

(ii) TRUE (3 + 5 = 8; 8 is an even number)

(iii) TRUE (2 + 4 = 6; 6 is an even number)

(iv) FALSE (2 + 4 = 6; 6 is an even number)

(v) TRUE (2 + 3 = 5; 5 is an odd number)

(vi) FALSE (3 + 2 = 5; 5 is not an even number)

(vii) FALSE [The whole number set is {0, 1, 2, 3, 4 ...), whereas the natural number set is {1, 2, 3, 4 ...)]

(viii) TRUE [The whole number set is {0, 1, 2, 3, 4 ...), whereas the natural number set is {1, 2, 3, 4 ...)]

(ix) TRUE [That number is zero.]

(x) FALSE

(xi) FALSE

(xii) TRUE