The prime numbers under 20 are 2, 3, 5, 7, 11, 13, 17, and 19.
A prime number is a whole number greater than 1 that has only two divisors: 1 and itself. In other words, a prime number cannot be formed by multiplying two smaller whole numbers.
Here's a breakdown:
- 2: Divisible only by 1 and 2.
- 3: Divisible only by 1 and 3.
- 5: Divisible only by 1 and 5.
- 7: Divisible only by 1 and 7.
- 11: Divisible only by 1 and 11.
- 13: Divisible only by 1 and 13.
- 17: Divisible only by 1 and 17.
- 19: Divisible only by 1 and 19.
Note that 1 is not a prime number because it only has one divisor (itself). Numbers like 4, 6, 8, 9, 10, 12, 14, 15, 16, and 18 are not prime because they have more than two divisors. For example, 4 is divisible by 1, 2, and 4.
