Hmmm... let me think.
0= zero
5, 4
five, four
take out e, o, r, f
so 5 is V.
This letter V can represent 5 as Roman but 5=4
0 = ?
5 = 4
Let's do the word play:
take out iv out of five. 4
There is Roman numeral inside the word 'five' to represent 5 instead.
So...
let's list out:
I, V
Remainder: F, E
There's e in zero.
And there is two numbers with same letter: F
The alphabet letter F can represent anything.
F,O,U,R and F,I,V,E and Z,E,R,O
let's cross out: O,R,E
Remainders: F,U,I,V,Z
So I guess: zero = E
5 = 4
4 = F
Why I think of this way? I was thinking of Roman numeral: 5 is V, 4 is IV
Those 4 and 5 has roman numerals inside to represent the digit as 5 has Roman numerl of 4
and 4 itself has none but has the letter 'F'.
The reason is there are two same letter and the letter 'E' has appear in the word 'zero', they can't be use as they already mentioned before. There are only one letter to represent and four isn't prime number but five is.