That is very difficult; I daresay most people can't do it. It requires keeping lots of numbers in memory.
Chat with our AI personalities
You divide the number by 2. If the number is able to divide WITHOUT a remainder, then it is a prime number. If you divide a number by 1, you will get the same number. That is not a prime number.
It is not a requirement. However, it is easier to divide mentally if the denominator is a rational number.
Compatible numbers can easily be divided mentally.
large numbers
Rational?