Why can't you mine several cryptocurrencies at once?

Question

Cryptography

What I mean is that there are many cryptocurrencies based (for example) on the Scrypt protocol. All of them require some small hash. Why can't you calculate some small hash and send it to all currencies at once? To some it will be winning, to some not, so be it?
So far, I only have an idea that the hash somehow depends on the block number or something else, but I would like clarity.

Answer 1

Do you know mathematics? Well, just a little?
Did you go here en.wikipedia.org/wiki/Hash ?
Hint, the hashing functions are different.

Answer 2

Why can't you calculate some small hash and send it to all currencies at once?

Because they send not a hash, but a parameter that, when substituted into the next block in the mining chain, gives such a hash. The block structure of different currencies is different, the history of mining is different, so the chances that the same data will give a suitable hash for several currencies are vanishingly small.