Page 298 - Ganit Kaushal

10. 404, 505, 444, 555, 454, 545. (A total of 6-palindromes) 9. (c) 10. (d) 11. (a) 12. (d)
NOTE: There can many more answers, we have given a few. 13. (a) 1 (b) 2 (c) 0 (d) 7368
11. dad, mom, noon, madam, racecar, malayalam. (e) 94435 (f) 13931 (g) divisor (h) 14

12. 01.10 pm, after 49 min; The next one 02.20 pm; after (i) 10,001
70 min.
13. 14 different calendars. 14. (a) False (b) False (c) True
Exercise 3.5 (d) False (we reach 6174) (e) False (ends at 1)
1. (a) 51000 + 52000 = 103000 (6-digit number) (f) False (its 35) (g) False (h) True
(b) Not possible;  10,000 + 10,000 = 20,000. The (i) False (It is 900000) (j) True (k) True
sum of two least five-digit numbers is 20,000. 15. 15, 46, 23, 70, 35, 106, 53, 160, 80, 40, 20, 10, 5, 16,

(c) 90,000 – 50,000 = 40,000 < 56,503 8, 4, 2, 1
(d) 10,000 – 100 = 9,900 (4-digit number) 16. 9815 17. 399600 18. 235
(e) 13,000 – 3,220 = 9,780 (4-digit number) 19. Only 1 supercell; 62871. If we swap the digits 1 and

(f) 98,825 – 97,991 = 834 (3-digit number) 6 of 62871, we get the number 12876. (see figure)
NOTE: These answers are not unique except (b). Students can
have many more answers according to their thinking. 16,200 39,344 29,765
2. (a) 2048 (Hint: evaluate 16 × 64 + 32 × 32) 23,609 62,871 45,306
(b) 7250 (Hint: evaluate 18 × 125 + 8 × 250 + 4 × 19,381 50,319 38,408
500 + 1000)

3. 123 (Hint: calculate row wise. Find 2 × 7 × 3 + 3(6 × Then we get 4 supercells shown by coloured in the
adjoining supercell grid figure.
4 + 3))

4. (a) 12, 6, 3, 10, 5, 16, 8, 4, 2, 1 20. The largest number in the group is 73,999; The smallest
(b) 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1 member of the group is 11,111; 51,111 is closest to
50,000.
(c) 28, 14, 7, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10,
5, 16, 8, 4, 2, 1. 21. 18000, 370, 300
(d) 39, 118, 59, 178, 89, 268, 134, 67, 202, 101, NOTE: This answer is not unique. This is one set of answer,
students may explore more
304, 152, 76, 38, 19, 58, 29, 88, 44, 22, 11, 34,
17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1. 22. 1358 [Hint: smallest = 101234; greatest = 99876]
5. 121 6. 104 7. 1300 8. 28 23. 2255, 2525, 2552, 5225, 5252, 5522; 23331
9. 1640 [Hint: Get the numbers by fixing the positions of Two
Exercise 3.6 2’s]
1. (a) 5000, less by 90; 5090, equal. 24. Three [Hint: 100 × 100 × 100 = 1 million]
( actual value = 5090) 25. Sum [Hint: product of first 15 whole numbers is 0]
(b) 61100, less by 35; 61130, less by 5. 26. (a) 900 (b) 1230 (c) 87650
( actual value = 61135) 27. (a) 900 (b) 2200 (c) 87700
2. (a) 15000000, less by 3435971. 28. 1400 km
( actual value = 18435971) 29. This is guessing work, different students may have

(b) 270000, greater by 1750. different answers according to their logic.
( actual value = 268250) Assertion Reason Type Questions
3. (a) 50 (b) 300000 1. (a) 2. (b) 3. (d) 4. (a)
4. There is no fixed answer, it depends on each individual. 5. (c) 6. (c) 7. (d) 8. (c)
5. There is no fixed answer.
8. (a) 1500 (b) 19500 (c) 2037200 (d) 430900 9. (b) 10. (c) 11. (c) 12. (a)
(e) 19980000 (f) 1200000 13. (a) 14. (c)
(g) 900000 (h) 3800 Case Study Based Questions
Miscellaneous Exercise 3.7 1. `7,25,700 2. `7,00,000
1. (a) 2. (d) 3. (a) 4. (a) 3. 1250 notes 4. `725700
5. (b) 6. (a) 7. (d) 8. (a) 5. Estimated amount is same the actual amount.

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