This question could be trivial but I don't know the answer.

Lets assume I have a real number, any real number.

$\displaystyle \forall x\in \mathbb{R}$

for example 1220,74 = 1220.

Of course we can see the integer part directly or we can use calculator or computer. But how to calculate without calculator/computer the $\displaystyle \mathbb{Z}$ part from any real number if exists?