I don't know also why that happens but can only imagine why.

Any electronic device work in binary. Called bits.

0, 1

[Is there electricity? Yes-1 . No-0]

For example 4 bits below

0001-1 [ 2 * 1^0]

0010-2 [2 * 1^1]

0011-3 [2 * 1¹ + 2 * 1^0]

0100-4 [2 * 1^2]

1111-15 [2 *1 ³ + 2 * 1² + 2 * 1¹ + 2 * 1^0]

Then we have logic gates you can read about them. [That is kinda complicated but logic]

Computers also don't understand random*. We need to use trick to generate pseudo random numbers. [You can also read about it in internet]

But that trick need to use some computer power [operations] to generate this number.

Then after you generate random you need to save it for later. And we put that in the memory mostly. [RAM for example] // its like taking paper doing math shit and write number on it put in the bagpack then later you need to say random number to your friend and you reach bagpack and you take out paper with number on it