Q1. What are co-prime numbers? Give examples.
Q2. Find the common factors of 12, 16 and 18.
Q3. A list consists of the following pairs of numbers:51, 53 ; 55 , 57 ; 59, 61 ; 63 , 65 ; 71, 73 Categorize them as pairs of:
i. co-primes ii. Primes iii Composite
Q5. Find the common factors of 5, 15 and 25.
Q6. Find the first three common multiples of 12 and 18.
Q7. Which of the following numbers are Co-Prime?
1) 18 and 35
2) 15 and 37
3) 81 and 16
Answers
Answer:
Ans 1. Any set of numbers which do not have any other common factor other than 1 are called co-prime or relatively prime numbers. This shows that 5 and 6 have no common factor other than 1. Therefore, they are co-prime numbers.
Ans 2. Factors for 12: 1, 2, 3, 4, 6, 12
Factors for 16: 1, 2, 4, 8, 16
Factors for 18: 1, 2, 3, 6, 9, 18.
Ans 3.(I) Co-prime number is a set of numbers or integers which have only 1 as their common factor i.e. their highest common factor (HCF) will be 1.
51,53− is pair of co-primes
55,57− is pair of co-primes
59,61− is pair of co-primes
63,65− is pair of co-primes
67,69− is pair of co-primes
71,73− is pair of co-primes
ii) A prime number is one which is only divisible by 1 and itself.
Pair of Prime Numbers from given pairs of numbers:
59,61
In other pairs there is one composite number.
iii) A composite number is a positive integer. which is not prime (i.e., which has factors other than 1 and itself).
Pair of Composite Numbers from given pairs of numbers:
55,57 and 63,67
In other pairs there is one prime number.
Ans 5. the common factors of 5, 15 and 25 are 1 and 5.
Ans 6. Multiples of 12 are 12, 24, 36, 48, 60, 72, 84, 96, 108, 12 …..
Multiples of 18 are
18, 36, 54, 72, 90, 108, 126, 144, 162, 180 ….
Hence, the first two common multiples of 12 and 18 are 36 and 72.
Step-by-step explanation:
Hope it's help
Answer:
last one is
Step-by-step explanation:
18 and 35
81 and 16
