PLAYING WITH NUMBERS
Class-6 Maths Practice Problems
Practice worksheet-2 for chapter playing with Numbers
1. Which number is not factor of 9?
(a) 5 (b) 3
(c) 1 (d) none
1. (a) since, the factors of 9 are 1 ´3 ´3
Thus,5 is not factor of 9.
2. The number which are multiple of 2 are called
(a) odd number (b) even number
(c) integers (d) none
2. (b) the numbers which are multiple of 2 , called even number.
3. Successor of every odd number is
(a) odd (b) even
(c) irrational (d) integer
3. (b) since 1+1=2
3+1=4
5+1=6
7+1=8
these are even numbers.
4. If 21 divide by 3 then we have quotient …..
(a) prime number (b) even number
(c) integer (d) 0
4. (a) 21 ÷ 3=7
and 7 is a prime number.
5. The prime factors of 36 are
(a) 2 ´3 ´4 ´7 (b) 2 ´2 ´3 ´3
(c) 2 ´5 ´6 ´7 (d) 1 ´2 ´3 ´4
5. (b) the prime factors of 36 are 2 ´2 ´3 ´3 .
6. The prime numbers between 0 to 20 are
(a) 2,3,5,7,11,13,17,18 (b) 2,3,5,7,11,13,17,20
(c) 2,3,4,5,6,7,8,9,10,11 (d) 2,3,5,7,11,13,17,19
6. (d) by the definition of prime number “a number which has exactly two
factors (1, itself). is called a prime number.”
7. Every number is a multiple of ……..
(a) 0 (b) 1
(c) -1 (d) none
7. (b) since 1 ´1=1,1 ´2=2,1 ´3=3,1 ´4=4
so 1 is factor of every number or every number is a multiple of one
8. The H.C.F of 9 and 27
(a) 9 (b) 3
(c) 2 (d) 27
8. (a) since 9=3 ´3
and 27=3 ´3 ´3
Thus, the highest common factors between 9 and 27 is 9.
9. First three odd and even number are…………………respectively.
(a) 1,3,5 and 2,4,6 (b) 0,1,2 and 0,2,4
(c) 2,3,5 and 4,6,7 (d) 2,4,6 and 1,3,5
9. (a) first three odd number are 1,3,5
first three even number are 2,4,6.
10. The definition of composite number
(a) A number, which has more than two factors, is called a composite number.
(b) A number, which has exactly two factors, is called a composite number.
(c) Both (a) and (b)
(d) None
10. (a) This is a right answer.
11. Which of the following number is divisible by 9?
(a) 2952 (b) 2953
(c) 2954 (d) 2950
11. (a) by the divisibility test of 9
If the sum of given digit is divisible of 9,then it is divisible by 9.
Here, 2+9+5+2=18
18 is divisible by 9.
12. Which of the following number is divisible by 6?
(a) 12930 (b) 12935
(c) 12933 (d) 12934
12. (a) 12930 is divisible by 2 and 3. and 1+2+9+3+0=15,is divisible by 3.
Then it is also divisible by 6.
13. The smallest 5-digits number, which is exactly divisible by 9,15,18, is
(a) 999 (b) 9990
(c) 99989 (d) 9995
13. (b) The L.C.M of 9,15,18 is
2 9, 15, 18
3 9, 15, 9
3 3, 5, 3
5 1, 5, 1
1, 1, 1
2 ´ 3 ´ 3 ´ 5=90.
The smallest 5-digit number is 10000.
If we divide 10000 by 90, then we get remainder 10
Then required smallest 5-digit number = 10000-10=9990.
14. Which is greatest prime number in the following?
(a) 2 (b) 3
(c) 91 (d) 97
14. (D) 97 is the greatest prime number in given.
15. The twin prime numbers in the following is
(a) 2,4 (b) 3,5
(c) 7,11 (d) 13,17
15. (b) Two prime numbers are said to be twin primes , if their difference is 2.
2
Here ,3 and 5 are prime number and their difference is 2.
16. In the following which numbers of pair is co-prime
(a) (2,4) (b) (2,3)
(c) (3,9) (d) (4,16)
16. (b) Two numbers are said to be co-prime, if they do not have a common
factor other than 1. Here, (2,3).
17. Which numbers is multiple of 11.
(a) 122 (b) 132
(c) 110 (d) (b) and (c) both
17. (d) The factors of 132 is 2 ´ 2 ´ 3 ´ 11
and 110=2 ´ 5 ´ 11
so (b) and (d) are multiple of 11.
18. Predecessor of 8 is
(a) a even number (b) a odd number
(c) a prime number (d) odd and prime number both
18. (d) 8-1=7 is an odd and prime number.
19. Predecessor of every even number is
(a) prime number (b) odd number
(c) both (d) none
19. (b) since 2-1=1,4-1=3,8-1=7
1,3,7 are odd number.
20. Greatest 4-digits number which is divisible by 4,6,12 is…….
(a) 9997 (b) 9996
(c) 9998 (d) 9995
20. (b) firstly we shall find the L.C.M of 4,6,12 .
the L.C.M of 4,6,12 is 12.
The greatest 4-digit number is 9999.
If we divide 9999 by 12,then we get remainder 3.
The required number =9999-3=9996.
21. H.C.F of two numbers =………
(a) Product of two numbers ´L.C.M
(b) Product of two numbers ÷ L.C.M
(c) both
(d) none
21. (b) since,
product of two numbers=L.C.M ´H.C.F
thus, L.C.M=product of two number ÷ H.C.F
22. -1 is an………
(a) Integer (b) irrational
(c) natural number (d) none
22. (a) all negative, zero and positive numbers are called integer.
23. The sum of all prime numbers between 10 to 25 is..
(a) 84 (b) 86
(c) 85 (d) 83
23. (d) prime numbers between10 to 25 are
11,13,17,19,23, the sum of these numbers =11+13+17+19+23
=83
24. All the factors of 25 are
(a) 1,5,25 (b) 1,5,15
3
(c) 1,5,20 (d) 1,2,4
24 (a) 25 divided exactly by 1,5,25
Thus the factors of 25 are 1,5,25.
25. The H.C.F of 35,42 and 77 is……
(a) 7 (b) 6
(c) 5 (d) 2
25 (a) Prime factors of 35=5 ´7
42=2 ´3 ´7
77=11 ´7
the highest common factor between these 7.
