We all know the prime numbers. Any number which is only divisible by '1' is called a prime number. Do you know what is coprime? First of all, it is a relative term, i.e. we can't say any number coprime...
Suppose there are 'n' number of different things. You would like to 'select' or 'arrange' all or some of those things in an order. In how many unique ways can you do so? Permutations and combinations is...