6th Maths: Term 1 Unit 1 : Numbers
Exercise 1.5 Questions with Answers & Solutions
1. Fill in the blanks
(i) The difference between the smallest natural number and the smallest whole number is __________.
Answer: one
(ii) 17 × __________ = 34 × 17
Answer: 34
(iii) When __________ is added to a number, it remains the same.
Answer: zero
(iv) Division by __________ is not defined.
Answer: zero
(v) Multiplication by __________ leaves a number unchanged.
Answer: one
2. Say True or False
(i) 0 is the identity for multiplication of whole numbers. [False]
(ii) Sum of two whole numbers is always less than their product. [False]
(iii) Both addition and multiplication are associative for whole numbers. [True]
(iv) Both addition and multiplication are commutative for whole numbers. [True]
(v) Multiplication is distributive over addition for whole numbers. [True]
3. Properties Illustrated
(i) 75 + 34 = 34 + 75
→ Commutativity for addition
→ Commutativity for addition
(ii) (12 × 4) × 8 = 12 × (4 × 8)
→ Associativity for multiplication
→ Associativity for multiplication
(iii) 50 + 0 = 50
→ Zero is Additive Identity
→ Zero is Additive Identity
(iv) 50 × 1 = 50
→ One is Multiplicative Identity
→ One is Multiplicative Identity
(v) 50 × 42 = 50 × 40 + 50 × 2
→ Distributivity of multiplication over addition
→ Distributivity of multiplication over addition
4. Simplify using Properties
(i) 50 × 102
= 50 × (100 + 2)
= (50 × 100) + (50 × 2)
= 5000 + 100 = 5100
= (50 × 100) + (50 × 2)
= 5000 + 100 = 5100
(ii) 500 × 689 − 500 × 89
= 500 (689 − 89)
= 500 × 600
= 3,00,000
= 500 × 600
= 3,00,000
(iii) 4 × 132 × 25
= 132 × (25 × 4)
= 132 × 100 = 13,200
= 132 × 100 = 13,200
(iv) 196 + 34 + 104
= (196 + 4) + 100 + 34
= 200 + 100 + 34
= 334
= 200 + 100 + 34
= 334
Objective Type Questions
5. (53 + 49) × 0 is
(a) 102
(b) 0
(c) 1
(d) 53 + 49 × 0
6. 59/1 is
(a) 1
(b) 0
(c) 1/59
(d) 59
7. The product of a non-zero whole number and its successor is always
(a) an even number
(b) an odd number
(c) zero
(d) none of these
8. The whole number that does not have a predecessor is
(a) 10
(b) 0
(c) 1
(d) none of these
9. Which of the following expressions is not zero?
(a) 0 × 0
(b) 0 + 0
(c) 2 / 0
(d) 0 / 2
10. Which of the following is not true?
(a) (4237 + 5498) + 3439 = 4237 + (5498 + 3439)
(b) (4237 × 5498) × 3439= 4237 × (5498 × 3439)
(c) 4237 + 5498 × 3439 = (4237 + 5498) × 3439
(d) 4237 × (5498 + 3439) = (4237 × 5498) + (4237 × 3439)
Summary Answer Key: Exercise 1.5
| Q.No | Answer |
|---|---|
| 1 | (i) 1 (ii) 34 (iii) 0 (iv) Zero (v) one |
| 2 | (i) False (ii) False (iii) True (iv) True (v) True |
| 3 | (i) Commutativity (ii) Associativity (iii) Additive Identity (iv) Multiplicative Identity (v) Distributivity |
| 4 | (i) 5100 (ii) 3,00,000 (iii) 13,200 (iv) 334 |
| 5 | (b) 0 |
| 6 | (d) 59 |
| 7 | (a) an even number |
| 8 | (b) 0 |
| 9 | (c) 2/0 |
| 10 | (c) 4237 + 5498 × 3439 = (4237 + 5498) × 3439 |