Prime Numbers Practice Answers #

1. A prime number is a number that has exactly two factors: 1 and itself. In other words, it can only be divided evenly by 1 and itself.
2. The prime numbers between 20 and 30 are: 23, 29
3. 1 is not considered a prime number because it only has one factor (itself). Prime numbers must have exactly two factors.
4. Let’s check if 27 is prime:
   27 ÷ 2 = 13.5 (not divisible)
   27 ÷ 3 = 9 (divisible!)
   Since 27 is divisible by 3, it is not prime. It’s a composite number.
5. The first five prime numbers are: 2, 3, 5, 7, 11