[A.K]

Hello Everyone!
I am new here.
I am a Mech. Eng, and I do self studies in Chemistry during my spare time.
I am reading a Chemistry book By Sir. McMurry and Fay. During chapter 3 page97, topic 3.11 percent composition, I have encountered a term that I didn't quite get it yet even after several researches on google and in the library so here is a quote from the author:
"the strategy is to find the relative number of moles of each element in the compound and then use the numbers to establish the mole ratios of the elements"
My first question is:
1. What does is the definition of Relative number in chemistry?
2. Why did the author didn't  say the actual number of moles instead of relative number of moles?
3. If we are relating the number of moles, to whom are we relating to? are we relating it to the other element in the compound that we have just discovered itself? or we are relating it to another element from a different chemical compound?
Thanks

[Borek]

Relative to each other - when you are calculating percent composition actual number of moles doesn't matter as in the final calculation it is the ratio of number of moles that matters.

For example compounds AB, A₂B₂, A₃B₃ (and so on) have the same percent composition.