If you have to guess then you might be challenged, but not retarded. You could still be eligible for lots of retard benefits though, like student loan forgiveness.
To be really retarded you have to believe that a mathematical formula can create a progression of random numbers.
For example the formula "times 2, minus 6, times 4"
You start with any number and it produces a random number that can be used to create secret keys that will bypass most pattern finding software.
Start with
"6", times 2 = 12, minus 6 = 6, times 4 = 24, and obviously 24 is a random number.
or "8", times 2 = 16, minus 6 =10, times 4 = 40, and 40 is random.
So you start with a sequence, 6, 7, 8 etc and you can produce random numbers to create keys for a digital currency.