"Many" and "much"

Dear teachers,

I am a bit confused about these two words. I was told by my teachers that use "many" with countable noun, while "much" with uncountable ones.

First, is that true?
Second, if that's true, then what about this:

"I didn't see much difference"

Why don't we say "I didn't see many difference"?

Something must be wrong here

Thanks for any help

[Tdol]

'Difference' can be both countable and uncountable:

I don't see much difference
I don't see many differences

thanks.
Didn't notice that before...

[Nolan]

Hi,
If you go to Usingenglish.com you will find an exercise on"Many & Much. this will make it clear to you.
Good luck
Nolan