Mathematics for IGCSE & O level - Number (Section 1)
1
Which of the following is a composite number?
отговор
(D)
12
2
Identify a pair of numbers where their HCF is 1.
отговор
(C)
7 and 10
3
What is the reciprocal of 1/5?
отговор
(B)
5
4
What is the simplified fraction for 0.5?
отговор
(A)
1/2
5
What are the prime factors of 42?
отговор
(A)
2, 3, 7
6
Which of the following is a prime number?
отговор
(C)
23
7
Which statement is true about the reciprocal of a number?
отговор
(B)
The reciprocal of a whole number is always a fraction.
8
Which of the following is the same as 0.666...
отговор
(B)
2/3
9
Which of the following statements are true regarding the highest common factor (HCF)?
отговор
A
B
D
10
Which of the following are rational numbers?
отговор
A
C
D
11
A rectangle has dimensions 240 mm by 204 mm. What is the largest possible side length for identical squares that can cover the rectangle completely?
отговор
(B)
12 mm
12
Which of these is a correct description of a rational number?
отговор
(B)
A number that can be expressed as a terminating or recurring decimal.
13
Which of the following is a common factor of 18 and 24?
отговор
(C)
3
14
What is the HCF of 12 and 15?
отговор
(B)
3
15
Which of the following is equivalent to 0. 25?
отговор
(C)
1/4
16
Which of the following is NOT a rational number?
отговор
(C)
√2
17
What is the reciprocal of -2?
отговор
(B)
-1/2
18
The prime factorization of 120 is 2^3 x 3 x 5. Based on this, which of the following is a factor of 120?
отговор
(C)
6
19
What are the prime factors of 28?
отговор
(B)
2, 2, 7
20
What are the prime factors of 18?
отговор
(B)
2, 3, 3
21
What is the LCM of 8 and 10?
отговор
(B)
40
22
What is the next number in the sequence: 2, 3, 5, 7, ...?
отговор
(D)
11
23
The HCF of two numbers is 7, and the LCM is 42. If one of the numbers is 14, what is the other number?
отговор
(C)
21
24
What type of number is √16?
отговор
(B)
Integer
25
Which statement about prime numbers is correct?
отговор
(C)
There are infinitely many prime numbers.
26
Which of the following numbers is NOT a factor of 36?
отговор
(D)
11
27
What is 5^2 - 3^2?
отговор
(B)
16
28
What is the LCM of 15 and 20?
отговор
(C)
60
29
What are the first four prime numbers?
отговор
(B)
2, 3, 5, 7
30
What is the lowest common multiple (LCM) of 4 and 6?
отговор
(B)
12
31
The HCF of two numbers is 5. The LCM of the same two numbers is 60. If one of the numbers is 15, what is the other number?
отговор
(A)
10
32
What is the prime factorization of 50?
отговор
(B)
2 x 5^2
33
What is the square root of 144?
отговор
(B)
12
34
If a bus leaves a station every 40 minutes and a train leaves the same station every 45 minutes, at what time will they next leave the station together, assuming they both left the station at 7:00 am?
отговор
(A)
10:00 am
35
What is the value of √81?
отговор
(B)
9
36
What is the HCF of 16 and 24?
отговор
(C)
8
37
What is the highest common factor (HCF) of 24 and 36?
отговор
(B)
12
38
The HCF of two numbers is 3. The LCM of the same two numbers is 18. If one number is 6, what is the other number?
отговор
(C)
9
39
What is the product of the prime factors of 30?
отговор
(B)
30
40
What is the prime factorization of 72?
отговор
(C)
2^3 x 3^2
41
Which number has the prime factors 2, 3, and 5?
отговор
(C)
30
42
Which of the following is an example of a recurring decimal?
отговор
(B)
0.333...
43
Two lighthouses flash at intervals of 22 seconds and 16 seconds, respectively. If they flash together at 10:00 PM, when will they next flash together?
отговор
(B)
10:04 PM
44
Which of the following sets of numbers are all natural numbers?
отговор
(B)
1, 2, 3, 4
45
Which of the following is NOT a property of prime numbers?
отговор
(C)
They are all odd numbers.
46
What is the reciprocal of 2/3?
отговор
(C)
3/2
47
What is the name for a number that cannot be written as a fraction?
отговор
(C)
Irrational number
48
Which of the following numbers is NOT a natural number?
отговор
(A)
0
49
Which set of numbers are all integers?
отговор
(B)
-3, 0, 5, 9
50
If the LCM of two numbers is 36 and their HCF is 6, which of the following pairs could be the two numbers?
