Page 46 - Start Up Mathematics_6

Some NCERT Textbook Questions

1. Find the value of the following:

(a) 297 × 17 + 297 × 3 (b) 54279 × 92 + 8 × 54279
(c) 81265 × 169 – 81265 × 69 (d) 3845 × 5 × 782 + 769 × 25 × 218
2. A vendor supplies 32 litres of milk to a hotel in the morning and 68 litres of milk in the
evening. It the milk costs ` 15 litre, how much money is due to the vendor per day?
3. Match the following:
(i) 425 × 136 = 425 × (6 + 30 + 100) (a) Commutativity under multiplication

(ii) 2 × 49 × 50 = 2 × 50 × 49 (b) Commutativity under addition
(iii) 80 + 2005 + 20 = 80 + 20 + 2005 (c) Distributivity of multiplication over addition
4. Which of the following will not represent zero:
0 10 – 10
(a) 1 + 0 (b) 0 × 0 (c) (d)
2 2
5. If the product of two whole numbers is 1, can we say that one or both of them will be 1?
Justify through examples.
6. Study the pattern:
1 × 8 + 1 = 9 1234 × 8 + 4 = 9876
12 × 8 + 2 = 98 12345 × 8 + 5 = 98765

123 × 8 + 3 = 987
Write the next two steps. Can you say how the pattern works?
(Hint: 12345 = 11111 + 1111 + 111 + 11 + 1)

Exemplar Problems

1. The product of successor and predecessor of 999 is:
(a) 999000 (b) 998000 (c) 989000 (d) 1998

2. A whole number is added to 25 and the same number is subtracted from 25. The sum of the
resulting numbers is:
(a) 0 (b) 25 (c) 50 (d) 75
3. Which of the following is not true?
(a) (7 + 8) + 9 = 7 + (8 + 9) (b) (7 × 8) × 9 = 7 × (8 × 9)
(c) 7 + 8 × 9 = (7 + 8) × (7 + 9) (d) 7 × (8 + 9) = (7 × 8) + (7 × 9)
4. Which of the following statements is not true?

(a) 0 + 0 = 0 (b) 0 – 0 = 0 (c) 0 × 0 = 0 (d) 0 ÷ 0 = 0
5. The successor of 1 million is:
(a) 2 millions (b) 1000001 (c) 100001 (d) 10001
6. Sum of the number of primes between 16 to 80 and 90 to 100 is:

(a) 20 (b) 18 (c) 17 (d) 16

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