Take any two digit number, reverse its digits, and subtract the smaller number from the larger?
For example:
I've tried this a few times and I never seem to end up with a prime number. Try some examples on your own. Do you ever end up with a prime number?
For example:
- Choose the number 42
- 42- 24 = 18
- 18 is not a prime number
I've tried this a few times and I never seem to end up with a prime number. Try some examples on your own. Do you ever end up with a prime number?
- Can you prove that you will never end up with a prime?
- What happens when I do the same with a three digit number?
- What about a four digit number?
- What about a five, six, seven, ... n digit number?
- Can you justify your findings?