Exercise 3.4
1. Find the common factors of :
(a) 20 and 28 (b) 15 and 25 (c) 35 and 50 (d) 56 and 120
2. Find the common factors of :
(a) 4, 8 and 12 (b) 5, 15 and 25
3. Find first three common multiples of :
(a) 6 and 8 (b) 12 and 18
4. Write all the numbers less than 100 which are common multiples of 3 and 4.
5. Which of the following numbers are co-prime?
(a) 18 and 35 (b) 15 and 37 (c) 30 and 415
(d) 17 and 68 (e) 216 and 215 (f) 81 and 16
6. A number is divisible by both 5 and 12. By which other number will that number be always divisible?
7. A number is divisible by 12. By what other numbers will that number be divisible?
Show Answer:
1. Find the common factors of :
(a) 1,2,4 (b) 1,5 (c) 1,5 (d) 1,2,4,8 2.
2. Find the common factors of :
(a) 1,2,4 (b) 1,5 3.
3. Find first three common multiples of :
(a) 24, 48, 72 (b) 36, 72, 108
4. Write all the numbers less than 100 which are common multiples of 3 and 4.
Ans- 12, 24, 36, 48, 60, 72, 84, 96
5. Which of the following numbers are co-prime?
Ans-(a) 18 and 35 (b) 15 and 37 (d) 17 and 68 (e) 216 and 215 (f) 81 and 16
6. A number is divisible by both 5 and 12. By which other number will that number be always divisible?
Ans- That number be always divisible- 60
7. A number is divisible by 12. By what other numbers will that number be divisible?
Ans- A number is divisible- 1,2,3,4,6,
