hello Smil333y - 4/4, 2/4, 3/4, 6/8, etc are time signatures.
4/4 means four beats per measure with a quarter note being one beat.
2/4 means 2 beats per measure with a quarte note being one beat.
3/4 means 3 beats per measure with a quarter note being one beat.
6/8 means six beats per measure with an eighth note being one beat.
4/4 time is 'march time'. 2/4 is 'quick march'. 3/4 and 6/8 are 'waltz times'.
Most rock & blues songs are in 4/4 time. To hear the difference between these time sigs, try this:
Beat your leg with your hand at a steady rate . . . keep the beat rate steady and keep it going as you do this . . .
To feel 4/4, count 1 2 3 4 1 2 3 4 and put some emphasis on the downbeats (1).
To feel 2/4, count 1 2 1 2 1 2 and put the emphasis on the downbeats (1).
To feel 3/4, count 1 2 3 1 2 3 and put the emphasis on the downbeats (1).
To feel 6/8, count 1 2 3 4 5 6 1 2 3 4 5 6 and put the emphasis on the downbeats (1).
There are other time signatures, but these are the most common.
For playing a song, it is important to get the right pulse going in your head since it will convey the basic rhythmic structure of the tune. If you try to play a waltz tune (3/4) in (4/4) time it will never sound right.
Hope this helps . . .
"That darn Pythagorean Comma thing keeps messing me up!"
[url]http://en.wikipedia.org/wiki/Pythagorean_comma[/url]