Is it true that all 2 digit prime numbers have a ones digit of 1,3,7 or 9 pls
Yes, it is true that all two-digit prime numbers have a ones digit of 1, 3, 7, or 9. To verify this, we can analyze the possible digits in the ones place for two-digit numbers.
A two-digit number can range from 10 to 99. Let's examine the possible digits for the ones place:
- If the ones digit is 0, the number is divisible by 10 and therefore not prime.
- If the ones digit is 2, 4, 6, or 8, the number is divisible by 2 and therefore not prime.
- If the ones digit is 5, the number is divisible by 5 and also not prime (except for the special case of 5 itself).
- If the ones digit is 1, 3, 7, or 9, the number is not divisible by 2 or 5, so it has a chance of being prime.
So, we can conclude that two-digit prime numbers must have a ones digit of 1, 3, 7, or 9.