tell me please

[dougiedog]

how to play a group of four sixteenth notes against three  eighth notes is it an absolute mathematical division or do you just feel it.  I used to drum and could do things like that but it was more feeling and there were only hands and feet involved not not ten fingers.

[keypeg]

You probably have an advantage with your drumming.  Each hand has its own rhythm and you're way ahead of the game.

[oscarr111111]

I'd start by analyzing the rhythm on sheet music, make sure you understand the rhythm technically (ie. where exactly each note cuts in against the other), and try to listen to it somewhere to get the sound into your head.  6 against 4 is very easy so I'd treat it as half a bar of that with the unaccented beats of the 4 sounded, get it right just by tapping the table with each hand then when you're a bit more comfortable sort out the accents, when you get comfortable tapping it go to play it on the piano.  Thats what I'd do.

[syncope]

I learned it by a saying a sentence a certain way, like a song: Thats the-way of coun-ting, but of course I can't show how it has to be said so thats no use haha

So another way is to subdivide and just see how 4 against 3 works like oscarr111111 suggested too:
you make twelve 32nd notes:
triplet is: iiii iiii iiii (per four)
sixteen group is: iii iii iii iii (per three)
you tick/say the twelve 32nd notes and get the triplet every four, and sixteen group every three

hope it works!

[faulty_damper]

how to play a group of four sixteenth notes against three  eighth notes is it an absolute mathematical division or do you just feel it.  I used to drum and could do things like that but it was more feeling and there were only hands and feet involved not not ten fingers.

It is not an absolute mathematical division.  You play it by using the beats as a guide.  As long as the first notes of the beat line up, the other notes will eventually fall into place even if the notes are uneven at first.

[keypeg]

It is not an absolute mathematical division.  You play it by using the beats as a guide.  As long as the first notes of the beat line up, the other notes will eventually fall into place even if the notes are uneven at first.

If the OP is a drummer and can already do that, should he not simply transfer those skills to piano? The only thing that is different is that the drummed beats now have a melody that are drummed out with different fingers.  He is way ahead of the game.

In fact, some piano students are sent out for drumming lessons.

[faulty_damper]

The difficulty in this situation is the ability to make an abstraction from a specific task (drumming) to another one (piano).

But, dougiedog didn't say he could actually play it, he said he probably could do it on drum.

Abstraction is a skill in itself.  The ability to abstract means to take something in one thing and apply it to another.  When a skill is required to do a task, that skill is only applicable to that task.  That skill becomes highly intertwined with it.  To make an abstraction is like removing a supporting pillar on a high-rise building; the building may collapse.

In more practical examples:
A student of mine was learning 2s vs 3s because she was playing the fourth movement from a sonata in F minor that required her to play 2s with 3s.  It took her weeks to finally be able to play it correctly but she was able to play it well.  Since the sonata only had 4 movements she was able to play the entire sonata and learn another piece.  I had picked out a piece that also had 2s vs 3s because it was a skill she had just learned so it wouldn't be so difficult.  I was wrong.

I thought, "why can't she play it right?  She just learned it in the sonata."

"I know I played it and I should be able to do the same here, right?" she said.

You see, she wasn't able to abstract the concept of 2s with 3s because she had learned only one example of it in the Beethoven sonata.  It only existed within that piece until the Prokofiev sonata.  It didn't take her as long to learn how to play those sections correctly but it was still difficult for her.  And when she finally learned the sonata, she now had two examples of 2s with 3s.

The next piece she chose also had 2s with 3s.  She didn't need my help to learn the polyrhythm this time because she learned how to abstract it and apply it to this piece.

In this situation it only took her to learn two pieces to make an abstraction of the 2s with 3s.  In other skills, it may require many examples before an abstraction can be made.

[Kassaa]

What's the use of counting
i           i             i           i
i                  i          i

I learned it this way, using the syllables of the sentence, try saying it with clapping/playing the three eight notes only (accented and rhytmical) and then fill the sixteenth notes in with your other hand/fingers.

This probably works better when someone first does it for you.

[keypeg]

Faulty - I have the impression that the OP already has the abstraction, but does not know whether it is permissible to bring it over.

We come to a new instrument and we don't know what is "allowed", and what might trip us up, so we don't dare try what we feel will work: and it will work!

A drummer knows how to handle these two rhythms.  But is it permitted?  Yes, it is permitted.  Teachers even send their students to drumming lessons.

So now you do, as a drummer, what you already know how to do, and add the pitch = melody.  Problem solved.

It would be silly to teach a drummer about rhythms, give him rhymes, show him pictorally how the two fit together - he can already do that.  He simply needs to know that it is ok to transfer his knowledge over to the piano.  If he KNOWS it's ok, he can do it - problem solved.