Question

1. Write true/false:

a) If a number is divided by 7, it must be divisible by 14.

b) If two numbers are coprime, at least one of them must be prime.

c) All numbers which are divisible by 6 must also be divisible by 3.

d) 31 and 43 are prime numbers.

e) 2 × 5 × 6 are the prime factors of 60.

2. Fill in the blanks:

a) The LCM of 5 and 1 will be _______.

b) The LCM of two coprime numbers is always equals to its _______.

c) ________ is a factor of every number.

d) The smallest multiple of 16 is _______.

e) The smallest whole number is ________.

3. Write down 6-digit smallest and greatest numbers and then find their

difference.

4. How many whole numbers are there between 15 and 40?

5. Write down separately the prime and composite numbers less than 30.

6. Find 23 + 56 + 12 in two ways.

7. Express 31 as the sum of three odd primes.

8. The numbers 17 and 71 are prime numbers. Both these numbers have

same digits 1 and 7. Find such pairs of prime numbers up to 100.​

Answer 1

Answer:

1)a)false

b)false

c)true

d)true

e)false

2)a) 5×1

b)LCM×HCF

c)1

e)0

3)

4)

5)

6)

7)

8)