## 1. Which of the following numbers is divisible by both 2 and 5?

### Answer:

### Explanation:

80 is even (divisible by 2) and ends in 0 (divisible by 5).

## 2. What is the smallest prime number?

### Answer:

### Explanation:

2 is the smallest and only even prime number.

## 3. Which of these numbers is a perfect square?

### Answer:

### Explanation:

64 is 8^2, making it a perfect square.

## 4. How many factors does the number 28 have?

### Answer:

### Explanation:

The factors are 1, 2, 4, 7, 14, and 28.

## 5. The HCF of two prime numbers is:

### Answer:

### Explanation:

Prime numbers have no common factors other than 1.

## 6. If a number is divisible by both 3 and 4, it is also divisible by:

### Answer:

### Explanation:

The LCM of 3 and 4 is 12.

## 7. The number 0 is:

### Answer:

### Explanation:

0 is neither classified as even nor odd.

## 8. Which number is not a composite number?

### Answer:

### Explanation:

1 is neither prime nor composite.

## 9. What is the next prime number after 5?

### Answer:

### Explanation:

7 is the prime number following 5.

## 10. The smallest composite number is:

### Answer:

### Explanation:

4 is the smallest number that is not prime and not 1.

## 11. If a number ends in 0, 2, 4, 6, or 8, it is:

### Answer:

### Explanation:

Numbers ending in 0, 2, 4, 6, or 8 are even numbers.

## 12. The number of factors a prime number has is:

### Answer:

### Explanation:

Prime numbers have only two factors: 1 and the number itself.

## 13. Which of these is a factor of every number?

### Answer:

### Explanation:

Every number is divisible by 1.

## 14. The number 11 is:

### Answer:

### Explanation:

11 is an odd prime number.

## 15. Which of these numbers is divisible by 9?

### Answer:

### Explanation:

The sum of digits of 981 is 18, which is divisible by 9.

## 16. Which is not a prime number?

### Answer:

### Explanation:

27 is 3^3 and hence not a prime number.

## 17. Which of the following numbers is divisible by both 6 and 8?

### Answer:

### Explanation:

72 is divisible by both 6 and 8.

## 18. Which of the following is the smallest even prime number?

### Answer:

### Explanation:

2 is the smallest and only even prime number.

## 19. What is the sum of the first two prime numbers?

### Answer:

### Explanation:

The sum of 2 and 5 is 7.

## 20. If a number is divisible by 2 and not divisible by 4, it must:

### Answer:

### Explanation:

Numbers ending in 2 or 6 are divisible by 2 but not by 4.