Practice Page 1

 Q1. What are prime numbers? ___________________________________________________ ___________________________________________________ Q2. What are composite numbers? ___________________________________________________ ___________________________________________________ Q3. Write all the prime numbers from 1 to 50. ___________________________________________________ ___________________________________________________ Q4. Write the prime number between 60 and 90. ___________________________________________________ Q5. Circle the prime numbers. 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 Q6. Can there be any natural number that does not have factor at all? ___________ Q7. Write down 7 consecutive numbers which are not prime numbers. ___________________________________________________ Q8. Express 31 as the sum of 3 odd prime numbers. ___________________________________________________

Practice Page 2

 Q1. What are co-prime numbers? Give example. ___________________________________________________ ___________________________________________________ Q2. Are all co-prime numbers are prime? ___________________________________________________ Q3. True/False. a.  The smallest composite number is 4. _________ b.  The smallest prime number is 1. ____________ c.  1 is neither prime nor composite.__________ d.   A prime number is a number that has only two factors i.e. 1 and itself. __________ e.   A number which has more than three factors is called a composite number. ____________ f.    All prime numbers are odd numbers. __________ g.   1 is co-prime with every number. ___________ h.   Every prime number is not a co-prime to each other. __________ i.     Any two successive numbers are always co-primed. __________ j.    The sum of two prime numbers is always a prime number. _______ k.   The H.C.F of two prime numbers is always 1. ________ Q4. Write two pair of prime numbers whose difference is 1. ___________________________________________________

Practice Page 3

 Fill in the blanks. a.   _______________ is the even prime number. b.   _______________ is the first composite number. c.   The smallest odd prime number is _____________. d.   ______________ is the neither prime nor composite number. e.   The sum two prime numbers can be even or__________. f.    14 and 15 is a pair of __________________ number. g.   H.C.F of two prime numbers is always _________. h.   ____________ are the prime numbers greater than 30 and less than 40. i.     73 is a ____________ number. j.    96 is a ____________ number. k.   Prime numbers are natural numbers that have only 2 factors i.e. 1 and_____________. l.     The two numbers are said to be co-prime numbers when there is no number, other than_______, that divides both the two given number evenly. m. A ____________ number has factors in addition to one and itself. n.   Every prime number except 2 is_______________. o.   If any whole number greater than 1 is not a prime number, then it is a _____________ number. p.   10, 12 and 18 are _______________ numbers.