Page 35 - classs 6 a_Neat

17. a. Estimate the sum of the following numbers to the nearest thousand.
PRACTICE EXERCISE 2 .5 31,750 + 47,807 + 12,397
b. Estimate the difference of the following numbers to the nearest thousand.
31,750 - 12,397
1. Find the LCM of the following numbers by the prime factorisation method.
a. 18,66 b. 24, 117 c. 60, 105,165
d. 140,180,220 e. 36, 72,96, 108 18. Compare the following Roman numerals using (>,<,=) after converting them into Arabic numerals.
a. DCCXLVI - DLXXXVII
b. CMLXIV - CMXLIX
2. Find the LCM of the following numbers by the common division method.
a.48, 64 b. 96, 128,240 c. 180, 360, 144 19. Simplify the following numerical expressions.
d.9,15,21 e. 19,57, 36
a. 60 - [48 - {63 + 3 - (12 - 9 + 3)}]
b. 99 + [17 - { 15 - 3(8 - 5)}]
3. Find the HCF and LCM of the following pairs of numbers. Show that the product of the HCF and LCM is the
same as the product of the given pair of numbers. 20 Find the HCF and the LCM of the following numbers and verify that the product of the numbers
a. 21, 27 b.13, 52 c. 225, 625 d. 120, 350 e.135, 162
= HCF × LCM
a.270, 450 b. 120, 350
4. The LCM of two numbers is 370 and the HCF is 1. If one of the numbers is 37, find the other number. What
type of numbers are these?
21. Find the largest number that will divide 398, 436 and 542 leaving behind remain ders of 7, 11 and 15,
respectively.
5. The product of two numbers is 15,870 and their HCF is 23. Find their LCM.

22. In the morning, three people, A, Band C start walking together. Their steps measure 80 cm, 90 cm and 100
6. The product of two numbers is 800 and their LCM is 400. Find their HCF.
cm, respectively. What is the minimum distance each should walk so that all can cover the distance in complete
steps?
7. Find the smallest number which when divided by 35, 56 and 105 leaves a remain der of 5 in each case.
10. A rectangular courtyard is 20 m 16 cm long and 15 m 60 cm broad. It is to be paved with square stones of
8. Four bells ring at intervals of 8, 10, 12 and 15 minutes, respectively. At what time will they again ring
simultaneously, if they rang together at 6 am the same size. Find the least possible number of stones that would be required.

9. Find the smallest four-digit number that is exactly divisible by 32, 36, 40 and 45.

10 Find the greatest six-digit number that is exactly divisible by 15, 18, and 24.

11. Can two numbers have 16 as their HCF and 204 as their LCM? Give the reason.

12. Replace in 27 20 with the smallest number such that it becomes divisible by 2, 3, 5, 7 and 9.

13. If three planets complete a revolution around the sun once every 200, 250 and 300 days, respectively,
when do they all come together again?

14. Write the predecessor and successor of the following numbers.
a. 24,689 b. 10,00,000

15. Write the following numbers in their expanded form.
a. 84,53,765 b. 5,00, 10,809

16. Rewrite the following numbers in the Indian system and the international system of numbers using
appropriate commas (,). Also, write the place value of the underlined digits in both the systems.
a.2219939 b.9891285375