Question

Whats the greatest whole number that uses all digits from 1 to 9

Answer 1

The greatest whole number using digits from 1 to 9, using the digits only once, is

987654321

Answer 2

Since our numeric system is positional, the digits further to the right are worth more than those to the left.

So, you want to assign a bigger coefficient to the digits which is more valuable in order to achieve the greatest number possible.

This means that the answer is simply 9876543210