On the first page (from the numbers 0 to 40), you may ONLY use the following:

- Addition (10 = 5 + 5)
- Subtraction (50 = 55 - 5)
- Multiplication (25 = 5 * 5)
- Division (1 = 5 / 5)
- Exponentiation (3125 = 5
^{5}) - Concatenation of 5's (60 = 55 + 5)
- Decimal separator (10 = 5 / .5)

For each new page (or 40 posts), you may introduce a new function or operator (!, !!, nCk, Fibonacci numbers... You can check the previous thread for more functions)

New functions allowed:

- Factorial (5! = 120)
- Root symbol (√(5 * 5) = 5,
^{.5}√(5 + 5) = 100) - Double Factorial (5!! = 15)

Some restrictions:

- No floor or ceiling
- No function that could make the game too easy (Nth prime, f(x) = x + 1...)

Any other ideas are welcome!

I will start with:

0 = (5 - 5) * (5 + 5 / .5)