CBSE Class 6 Mathematics Playing with Numbers Assignments Set 10

Question. Write all the factors of
(i) \( 36 \)
(ii) \( 45 \)
(iii) \( 13 \)
(iv) \( 256 \)
Answer:
(i) \( 1, 2, 3, 4, 6, 9, 12, 18, 36 \)
(ii) \( 1, 3, 5, 9, 15, 45 \)
(iii) \( 1, 13 \)
(iv) \( 1, 2, 4, 8, 16, 32, 64, 128, 256 \)

Question. Write \( 5 \) multiples of
(i) \( 18 \)
(ii) \( 13 \)
(iii) \( 15 \)
Answer:
(i) \( 18, 36, 54, 72, 90 \)
(ii) \( 13, 26, 39, 52, 65 \)
(iii) \( 15, 30, 45, 60, 75 \)

Question. Pick even and odd numbers
(i) \( 32 \)
(ii) \( 15 \)
(iii) \( 28 \)
(iv) \( 36 \)
Answer:
Even: \( 32, 28, 36 \)
Odd: \( 15 \)

Question. Write prime numbers from \( 1 \) to \( 25 \)
Answer: \( 2, 3, 5, 7, 11, 13, 17, 19, 23 \)

Question. Write prime numbers between \( 30 \) and \( 40 \)
Answer: \( 31, 37 \)

Question. Write
(i) Even prime number
(ii) Smallest prime number
(iii) Largest prime number before \( 97 \)
Answer:
(i) \( 2 \)
(ii) \( 2 \)
(iii) \( 89 \)

Question. Pick up the prime number(s)
(i) \( 63 \)
(ii) \( 1 \)
(iii) \( 21 \)
(iv) \( 89 \)
(v) \( 11 \)
Answer: \( 89, 11 \)

Question. Make a list of \( 7 \) consecutive numbers none of which is prime
Answer: \( 90, 91, 92, 93, 94, 95, 96 \)

Question. (i) Is there any natural number having no factor at all?
(ii) Find all the numbers having exactly one factor.
(iii) Find numbers between \( 1 \) and \( 100 \) having exactly three factors.
Answer:
(i) No
(ii) \( 1 \)
(iii) \( 4, 9, 25, 49 \)

Question. What are Composite numbers? Can a Composite number be odd? If the answer is yes, write the Smallest odd Composite number.
Answer: Composite numbers are numbers having more than two factors. Yes, a composite number can be odd, and the smallest odd composite number is \( 9 \).

Question. Express as the sum of three odd prime nos.
(i) \( 31 \)
(ii) \( 49 \)
Answer:
(i) \( 31 = 5 + 7 + 19 \)
(ii) \( 49 = 3 + 5 + 41 \)

Question. Express as the sum of twin primes.
(i) \( 36 \)
(ii) \( 144 \)
Answer:
(i) \( 36 = 17 + 19 \)
(ii) \( 144 = 71 + 73 \)