Question

product of three numbers is not equal to the product of their HCF and LCM.
EXERCISE 1.2
1. Express each number as a product of its prime factors:
(1) 140
(ii) 156 prime factor
(iii) 3825
(iv) 5005
(v) 7429
2. Find the LCM and HCF of the following pairs of integers and verify that LCM HCF=
product of the two numbers.
(1) 26 and 91
(*) 510 and 92
(iii) 336 and 54
3. Find the LCM and HCF of the following integers by applying the prime factorisation
method.
(i) 12,15 and 21 (ii) 17, 23 and 29
(iii) 8, 9 and 25
4. Given that HCF (306,657) = 9, find LCM (306, 657).
5. Check whether 6" can end with the digit 0 for any natural number n.
6. Explain why 7 x 11 x 13+ 13 and 7 x6x5 x 4x3x2x1 +5 are composite numbers.
7. There is a circular path around a sports field. Sonia takes 18 minutes to drive one round
of the field, while Ravi takes 12 minutes for the same. Suppose they both start at the
same point and at the same time, and go in the same direction. After how many minutes
will they meet again at the starting point?​

Answer 1

Answer:

₱ɽøđʉ₵₮ ø₣ ₮ⱨɽɇɇ ₦ʉ₥฿ɇɽ₴ ł₴ ₦ø₮ ɇqʉ₳ⱡ ₮ø ₮ⱨɇ ₱ɽøđʉ₵₮ ø₣ ₮ⱨɇłɽ Ⱨ₵₣ ₳₦đ Ⱡ₵₥.

ɆӾɆⱤ₵Ł₴Ɇ 1.2

1. Ɇӿ₱ɽɇ₴₴ ɇ₳₵ⱨ ₦ʉ₥฿ɇɽ ₳₴ ₳ ₱ɽøđʉ₵₮ ø₣ ł₮₴ ₱ɽł₥ɇ ₣₳₵₮øɽ₴:

(1) 140

(łł) 156 ₱ɽł₥ɇ ₣₳₵₮øɽ

(łłł) 3825

(łv) 5005

(v) 7429

2. ₣ł₦đ ₮ⱨɇ Ⱡ₵₥ ₳₦đ Ⱨ₵₣ ø₣ ₮ⱨɇ ₣øⱡⱡø₩ł₦₲ ₱₳łɽ₴ ø₣ ł₦₮ɇ₲ɇɽ₴ ₳₦đ vɇɽł₣ɏ ₮ⱨ₳₮ Ⱡ₵₥ Ⱨ₵₣=

₱ɽøđʉ₵₮ ø₣ ₮ⱨɇ ₮₩ø ₦ʉ₥฿ɇɽ₴.

(1) 26 ₳₦đ 91

(*) 510 ₳₦đ 92

(łłł) 336 ₳₦đ 54

3. ₣ł₦đ ₮ⱨɇ Ⱡ₵₥ ₳₦đ Ⱨ₵₣ ø₣ ₮ⱨɇ ₣øⱡⱡø₩ł₦₲ ł₦₮ɇ₲ɇɽ₴ ฿ɏ ₳₱₱ⱡɏł₦₲ ₮ⱨɇ ₱ɽł₥ɇ ₣₳₵₮øɽł₴₳₮łø₦

₥ɇ₮ⱨøđ.

(ł) 12,15 ₳₦đ 21 (łł) 17, 23 ₳₦đ 29

(łłł) 8, 9 ₳₦đ 25

4. ₲łvɇ₦ ₮ⱨ₳₮ Ⱨ₵₣ (306,657) = 9, ₣ł₦đ Ⱡ₵₥ (306, 657).

5. ₵ⱨɇ₵₭ ₩ⱨɇ₮ⱨɇɽ 6" ₵₳₦ ɇ₦đ ₩ł₮ⱨ ₮ⱨɇ đł₲ł₮ 0 ₣øɽ ₳₦ɏ ₦₳₮ʉɽ₳ⱡ ₦ʉ₥฿ɇɽ ₦.

6. Ɇӿ₱ⱡ₳ł₦ ₩ⱨɏ 7 ӿ 11 ӿ 13+ 13 ₳₦đ 7 ӿ6ӿ5 ӿ 4ӿ3ӿ2ӿ1 +5 ₳ɽɇ ₵ø₥₱ø₴ł₮ɇ ₦ʉ₥฿ɇɽ₴.

7. ₮ⱨɇɽɇ ł₴ ₳ ₵łɽ₵ʉⱡ₳ɽ ₱₳₮ⱨ ₳ɽøʉ₦đ ₳ ₴₱øɽ₮₴ ₣łɇⱡđ. ₴ø₦ł₳ ₮₳₭ɇ₴ 18 ₥ł₦ʉ₮ɇ₴ ₮ø đɽłvɇ ø₦ɇ ɽøʉ₦đ

ø₣ ₮ⱨɇ ₣łɇⱡđ, ₩ⱨłⱡɇ Ɽ₳vł ₮₳₭ɇ₴ 12 ₥ł₦ʉ₮ɇ₴ ₣øɽ ₮ⱨɇ ₴₳₥ɇ. ₴ʉ₱₱ø₴ɇ ₮ⱨɇɏ ฿ø₮ⱨ ₴₮₳ɽ₮ ₳₮ ₮ⱨɇ

₴₳₥ɇ ₱øł₦₮ ₳₦đ ₳₮ ₮ⱨɇ ₴₳₥ɇ ₮ł₥ɇ, ₳₦đ ₲ø ł₦ ₮ⱨɇ ₴₳₥ɇ đłɽɇ₵₮łø₦. ₳₣₮ɇɽ ⱨø₩ ₥₳₦ɏ ₥ł₦ʉ₮ɇ₴

• ₩łⱡⱡ ₮ⱨɇɏ ₥ɇɇ₮ ₳₲₳ł₦ ₳₮ ₮ⱨɇ ₴₮₳ɽ₮ł₦₲ ₱øł₦₮?