1 . Which of the following is a natural number?
a) 0
b) -1
c) 1
d) -5
Answer: c) 1
Explanation: Natural numbers are positive integers greater than zero.
2 . What is the successor of 9?
a) 8
b) 10
c) 9
d) 11
Answer: d) 11
Explanation: The successor of a number is the number that follows it. The successor of 9 is 10.
3 . Which of the following is not a natural number?
a) 2
b) 3
c) 0
d) 4
Answer: c) 0
Explanation: Natural numbers are positive integers, and 0 is not positive.
4 . What is the sum of the first ten natural numbers?
a) 45
b) 55
c) 65
d) 75
Answer: b) 55
Explanation: The sum of the first n natural numbers is given by the formula: n(n+1)/2. For n = 10, the sum is 10(10+1)/2 = 55.
4 . Which of the following is a composite number?
a) 1
b) 2
c) 3
d) 4
Answer: d) 4
Explanation: A composite number has factors other than 1 and itself. 4 is divisible by 1, 2, and 4.
5 . Which is the smallest prime number?
a) 0
b) 1
c) 2
d) 3
Answer: c) 2
Explanation: A prime number is a number that is divisible by 1 and itself only. 2 is the smallest prime number.
6 . Which of the following is not a prime number?
a) 11
b) 13
c) 15
d) 17
Answer: c) 15
Explanation: A prime number is a number that is divisible by 1 and itself only. 15 is divisible by 1, 3, 5, and 15, so it is not prime.
7 . What is the product of 5 and its successor?
a) 24
b) 25
c) 30
d) 35
Answer: b) 25
Explanation: The successor of 5 is 6. The product of 5 and 6 is 5 * 6 = 30.
8 . Which of the following is a perfect square?
a) 16
b) 17
c) 18
d) 19
Answer: a) 16
Explanation: A perfect square is a number that is the square of an integer. 16 is the square of 4.
9 . What is the greatest common factor of 24 and 36?
a) 4
b) 6
c) 8
d) 12
Answer: d) 12
Explanation: The greatest common factor (GCF) of two numbers is the largest number that divides both of them without leaving a remainder. The prime factorization of 24 is 2^3 * 3, and the prime factorization of 36 is 2^2 * 3^2. The common factors are 2^2 * 3 = 12, making it the GCF.
10 . Which of the following numbers is divisible by both 3 and 4?
a) 16
b) 18
c) 24
d) 27
Answer: c) 24
Explanation: To be divisible by both 3 and 4, a number must be a multiple of both 3 and 4. Among the options, 24 is divisible by both 3 and 4 since it is a multiple of 3 (24/3 = 8) and 4 (24/4 = 6).
11 . What is the smallest multiple of 8 and 12?
a) 16
b) 24
c) 48
d) 96
Answer: c) 48
Explanation: To find the smallest multiple of two numbers, we need to find their least common multiple (LCM). The LCM of 8 and 12 is 24. Therefore, the smallest multiple of 8 and 12 is 24.
12 . Which of the following is an odd number?
a) 20
b) 27
c) 36
d) 42
Answer: b) 27
Explanation: An odd number is not divisible by 2. Among the options, 27 is not divisible by 2, making it an odd number.
13 . What is the value of 10! (10 factorial)?
a) 45
b) 362,880
c) 1,000
d) 10,000
Answer: b) 362,880
Explanation: 10! (10 factorial) is the product of all positive integers from 1 to 10. Thus, 10! = 10 * 9 * 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 362,880.
14 . What is the least common multiple of 6 and 9?
a) 12
b) 18
c) 24
d) 36
Answer: b) 18
Explanation: The least common multiple (LCM) of two numbers is the smallest number that is divisible by both of them. The LCM of 6 and 9 is 18.
15 . Which of the following is a prime factor of 36?
a) 2
b) 3
c) 4
d) 6
Answer: b) 3
Explanation: Prime factors are the prime numbers that divide a given number. The prime factorization of 36 is 2^2 * 3^2. Therefore, 3 is a prime factor of 36.
16 . What is the sum of the first 20 even natural numbers?
a) 100
b) 200
c) 400
d) 800
Answer: c) 400
Explanation: The sum of the first n even natural numbers is given by the formula: n(n+1). For n = 20, the sum is 20(20+1) = 400.
17 . Which of the following numbers is a multiple of both 5 and 7?
a) 28
b) 35
c) 42
d) 49
Answer: b) 35
Explanation: To be divisible by both 5 and 7, a number must be a multiple of both 5 and 7. Among the options, 35 is divisible by both 5 (35/5 = 7) and 7 (35/7 = 5).
18 . What is the largest two-digit prime number?
a) 97
b) 101
c) 103
d) 109
Answer: a) 97
Explanation: A two-digit prime number is a prime number between 10 and 99. Among the options, 97 is the largest two-digit prime number.
19 . What is the product of the first five prime numbers?
a) 110
b) 115
c) 120
d) 130
Answer: c) 120
Explanation: The first five prime numbers are 2, 3, 5, 7, and 11. The product of these numbers is 2 * 3 * 5 * 7 * 11 = 210.
20 . What is the smallest common multiple of 8, 12, and 16?
a) 48
b) 96
c) 144
d) 192
Answer: b) 96
Explanation: The smallest common multiple (LCM) of three or more numbers is the smallest number that is divisible by all of them. The LCM of 8, 12, and 16 is 48. Therefore, the smallest common multiple is 96.
21 . What is the value of 0! (0 factorial)?
a) 0
b) 1
c) Undefined
d) Infinity
Answer: b) 1
Explanation: By convention, 0! (0 factorial) is defined to be 1.
22 . What is the next prime number after 31?
a) 33
b) 37
c) 39
d) 41
Answer: d) 41
Explanation: The next prime number after 31 is 41. Prime numbers are numbers that are divisible only by 1 and themselves.
23 . What is the sum of the digits in the number 456?
a) 12
b) 15
c) 18
d) 21
Answer: b) 15
Explanation: The sum of the digits in the number 456 is calculated by adding 4 + 5 + 6, which equals 15.
24 . Which of the following numbers is not a factor of 48?
a) 2
b) 6
c) 8
d) 12
Answer: b) 6
Explanation: A factor of a number divides it evenly without leaving a remainder. Among the options, 6 is not a factor of 48 because 48 divided by 6 leaves a remainder of 0.
25 . What is the smallest three-digit prime number?
a) 100
b) 101
c) 103
d) 107
Answer: c) 103
Explanation: A three-digit prime number is a prime number between 100 and 999. Among the options, 103 is the smallest three-digit prime number.
26 . What is the sum of the first 15 odd natural numbers?
a) 105
b) 120
c) 135
d) 150
Answer: a) 105
Explanation: The sum of the first n odd natural numbers is given by the formula: n^2. For n = 15, the sum is 15^2 = 225.
27 . What is the smallest common multiple of 9 and 12?
a) 18
b) 24
c) 36
d) 72
Answer: c) 36
Explanation: The smallest common multiple (LCM) of two numbers is the smallest number that is divisible by both of them. The LCM of 9 and 12 is 36.
28 . Which of the following is a prime number?
a) 27
b) 33
c) 37
d) 42
Answer: c) 37
Explanation: A prime number is a number that is only divisible by 1 and itself. Among the options, 37 is the only prime number.
29 . What is the value of 8! (8 factorial)?
a) 40,320
b) 32,768
c) 40,960
d) 42,240
Answer: a) 40,320
Explanation: 8! (8 factorial) is the product of all positive integers from 1 to 8. Thus, 8! = 8 * 7 * 6 * 5 * 4 * 3 * 2 * 1 = 40,320.
30 . What is the sum of the factors of 24?
a) 24
b) 36
c) 48
d) 60
Answer: c) 48
Explanation: The factors of 24 are 1, 2, 3, 4, 6, 8, 12, and 24. The sum of these factors is 1 + 2 + 3 + 4 + 6 + 8 + 12 + 24 = 48.
31 . Which of the following numbers is a perfect cube?
a) 25
b) 27
c) 32
d) 36
Answer: b) 27
Explanation: A perfect cube is a number that is the cube of an integer. 27 is the cube of 3, making it a perfect cube.
32 . What is the next prime number after 47?
a) 49
b) 51
c) 53
d) 55
Answer: c) 53
Explanation: The next prime number after 47 is 53. Prime numbers are numbers that are divisible only by 1 and themselves.
33 . What is the sum of the digits in the number 789?
a) 20
b) 24
c) 26
d) 30
Answer: c) 26
Explanation: The sum of the digits in the number 789 is calculated by adding 7 + 8 + 9, which equals 24.
34 . What is the greatest common factor of 15 and 25?
a) 3
b) 5
c) 15
d) 25
Answer: b) 5
Explanation: The greatest common factor (GCF) of two numbers is the largest number that divides both of them without leaving a remainder. The GCF of 15 and 25 is 5.
35 . Which of the following numbers is a factor of 63?
a) 7
b) 8
c) 9
d) 10
Answer: a) 7
Explanation: A factor of a number divides it evenly without leaving a remainder. 7 is a factor of 63 because 63 divided by 7 is equal to 9.
36 . What is the smallest multiple of 5 and 9?
a) 20
b) 36
c) 45
d) 90
Answer: c) 45
Explanation: The smallest multiple of two numbers is their least common multiple (LCM). The LCM of 5 and 9 is 45.
37 . Which of the following numbers is divisible by 5, 6, and 10?
a) 20
b) 30
c) 40
d) 50
Answer: b) 30
Explanation: To be divisible by 5, 6, and 10, a number must be a multiple of all three. Among the options, 30 is divisible by 5 (30/5 = 6), 6 (30/6 = 5), and 10 (30/10 = 3).
38 . What is the sum of the first 50 natural numbers?
a) 1225
b) 1275
c) 1325
d) 1375
Answer: b) 1275
Explanation: The sum of the first n natural numbers is given by the formula: n(n+1)/2. For n = 50, the sum is 50(50+1)/2 = 1275.
39 . What is the product of the first three prime numbers?
a) 2
b) 6
c) 10
d) 30
Answer: a) 2
Explanation: The first three prime numbers are 2, 3, and 5. The product of these numbers is 2 * 3 * 5 = 30.
40 . What is the sum of the first 25 even natural numbers?
a) 275
b) 500
c) 625
d) 750
Answer: b) 500
Explanation: The sum of the first n even natural numbers is given by the formula: n(n+1). For n = 25, the sum is 25(25+1) = 500.
41 . Which of the following numbers is a multiple of both 3 and 7?
a) 17
b) 21
c) 24
d) 28
Answer: b) 21
Explanation: To be divisible by both 3 and 7, a number must be a multiple of both 3 and 7. Among the options, 21 is divisible by both 3 (21/3 = 7) and 7 (21/7 = 3).
42 . What is the largest two-digit composite number?
a) 79
b) 89
c) 97
d) 99
Answer: d) 99
Explanation: A composite number is a number that has factors other than 1 and itself. Among the options, 99 is the largest two-digit composite number.
43 . What is the product of the first four natural numbers?
a) 10
b) 20
c) 24
d) 30
Answer: c) 24
Explanation: The product of the first n natural numbers is given by the factorial of n. For n = 4, the product is 4! = 4 * 3 * 2 * 1 = 24.
44 . What is the least common multiple of 7 and 9?
a) 7
b) 9
c) 63
d) 81
Answer: c) 63
Explanation: The least common multiple (LCM) of two numbers is the smallest number that is divisible by both of them. The LCM of 7 and 9 is 63.
45 . Which of the following is a prime factor of 42?
a) 2
b) 3
c) 4
d) 6
Answer: b) 3
Explanation: Prime factors are the prime numbers that divide a given number. The prime factorization of 42 is 2 * 3 * 7. Therefore, 3 is a prime factor of 42.
46 . What is the sum of the first 30 odd natural numbers?
a) 450
b) 525
c) 600
d) 675
Answer: a) 450
Explanation: The sum of the first n odd natural numbers is given by the formula: n^2. For n = 30, the sum is 30^2 = 900.
47 . Which of the following is not a factor of 72?
a) 6
b) 8
c) 9
d) 12
Answer: c) 9
Explanation: A factor of a number divides it evenly without leaving a remainder. Among the options, 9 is not a factor of 72 because 72 divided by 9 leaves a remainder of 0.
48 . What is the largest three-digit composite number?
a) 997
b) 998
c) 999
d) 1000
Answer: c) 999
Explanation: A composite number is a number that has factors other than 1 and itself. Among the options, 999 is the largest three-digit composite number.
49 . What is the product of the first six prime numbers?
a) 720
b) 840
c) 960
d) 1080
Answer: b) 840
Explanation: The first six prime numbers are 2, 3, 5, 7, 11, and 13. The product of these numbers is 2 * 3 * 5 * 7 * 11 * 13 = 840.
50 . What is the sum of the first 40 natural numbers?
a) 780
b) 820
c) 860
d) 900
Answer: b) 820
Explanation: The sum of the first n natural numbers is given by the formula: n(n+1)/2. For n = 40, the sum is 40(40+1)/2 = 820.