There are 4 one-digit counting numbers that are prime.
Prime Numbers Explained
A prime number is a whole number greater than 1 that has only two divisors: 1 and itself. Counting numbers are positive integers (1, 2, 3, ...). Therefore, we are looking for one-digit positive integers that are prime.
Identifying One-Digit Prime Numbers
Let's examine the one-digit counting numbers: 1, 2, 3, 4, 5, 6, 7, 8, and 9.
- 1: Not a prime number because it only has one divisor (itself).
- 2: A prime number because its only divisors are 1 and 2.
- 3: A prime number because its only divisors are 1 and 3.
- 4: Not a prime number because its divisors are 1, 2, and 4.
- 5: A prime number because its only divisors are 1 and 5.
- 6: Not a prime number because its divisors are 1, 2, 3, and 6.
- 7: A prime number because its only divisors are 1 and 7.
- 8: Not a prime number because its divisors are 1, 2, 4, and 8.
- 9: Not a prime number because its divisors are 1, 3, and 9.
Conclusion
The one-digit counting numbers that are prime are 2, 3, 5, and 7. Thus, there are 4 such numbers.
