25 Questions on Number system

                                                                       || Shree ||

Here are 25 unique and simple multiple-choice questions (MCQs) on the Number System for school competitive exams:

1. What is the smallest prime number?

A) 0
B) 1
C) 2
D) 3
Answer: C) 2

2. Which number is neither prime nor composite?

A) 0
B) 1
C) 2
D) 3
Answer: B) 1

3. The place value of 5 in 5,438 is:

A) 5
B) 50
C) 500
D) 5,000
Answer: D) 5,000

4. What is the LCM of 4 and 6?

A) 12
B) 24
C) 6
D) 18
Answer: A) 12

5. The HCF of 18 and 24 is:

A) 6
B) 12
C) 18
D) 24
Answer: A) 6

6. What is 111 in decimal form?

A) 1
B) 3
C) 7
D) 11
Answer: C) 7

7. Which of the following is a rational number?

A) √2
B) π
C) 4/5
D) √3
Answer: C) 4/5

8. The sum of the first five natural numbers is:

A) 10
B) 15
C) 20
D) 25
Answer: B) 15

9. Which number is an odd number?

A) 10
B) 20
C) 25
D) 30
Answer: C) 25

10. The number 0 is a:

A) Positive number
B) Negative number
C) Whole number
D) Prime number
Answer: C) Whole number

11. Which of the following is a perfect square?

A) 50
B) 81
C) 90
D) 99
Answer: B) 81

12. The smallest odd prime number is:

A) 1
B) 3
C) 5
D) 7
Answer: B) 3

13. What is the base of the decimal number system?

A) 2
B) 8
C) 10
D) 16
Answer: C) 10

14. What is the binary equivalent of the decimal number 5?

A) 10
B) 101
C) 100
D) 110
Answer: B) 101

15. The product of any two odd numbers is always:

A) Odd
B) Even
C) Prime
D) Composite
Answer: A) Odd

16. A number divisible by both 3 and 5 is always divisible by:

A) 2
B) 6
C) 15
D) 30
Answer: C) 15

17. What is the Roman numeral for 50?

A) X
B) L
C) C
D) D
Answer: B) L

18. The sum of two even numbers is always:

A) Odd
B) Even
C) Prime
D) Composite
Answer: B) Even

19. What is the largest 2-digit prime number?

A) 89
B) 97
C) 99
D) 91
Answer: B) 97

20. The number of digits in 10,000 is:

A) 4
B) 5
C) 6
D) 3
Answer: B) 5

21. Which of the following numbers is divisible by 9?

A) 123
B) 135
C) 147
D) 159
Answer: B) 135

22. If a number ends in 0, it is always divisible by:

A) 2
B) 5
C) 10
D) All of the above
Answer: D) All of the above

23. What is the sum of the digits of 456?

A) 14
B) 15
C) 16
D) 17
Answer: B) 15

24. The largest 3-digit number is:

A) 999
B) 1000
C) 998
D) 900
Answer: A) 999

25. How many prime numbers are there between 1 and 10?

A) 2
B) 3
C) 4
D) 5
Answer: C) 4