fractional parts

[Terry]

I have a question for the gnucash developer community regarding commodities,
stocks etc. and how they are priced, traded, listed, whatever.

I have always seen such things listed/priced/traded as single fractions, i.e., 

a single stock would be "listed" as :  234 1/8

or  234 3/8

or sugar sells for 3 for 1.00 or 1 for 1/3 USD (price,  not what I pay)

some of the common "fractions" I have seen are:

1/2, x/4, x/3, x/8, x/16, x/32

occasionally I have seen 5 for 1 USD or 1 for 1/5 USD (price, and what I pay)

10 for 1 USD (or 1 for 1/10 USD) is common

as is 1/6 or 1/12 ( 6 for 1 USD or 12 for 1 USD).

What I have never seen is the following (and I am having great difficulty in
trying to express this since I have never seen this in practice):

stock listed at 234 3/8 1/32 (i.e., 234 USD + 3/8 USD + 1/32 USD). 

What I am trying to express here is the use of more than one fraction to
express the units desired. The above could equivalently be expressed as:

234 13/32

but what about something like:

234 3/8 1/5 == 234 + 3/8 + 1/5 USD

That could equivalently be expressed as 

234 23/40

But that's not my point - I have never seen the use of more than one fraction.

My question - has anybody???? Would there be a reason for using more than one ?

This is not a trivial question - there is a valid reason for asking. The fact
that I have not seen this in practice and wouldn't make sense to me, does not
mean that it isn't used someplace. 

An ancillary question - what are the common fractions used. I have listed a few
above:

powers of 2: 1/2, 1/4, 1/8, 1/16, 1/32, 1/64 never seen anything higher

powers of 10: 1/10, 1/100, 1/1000,  never seen anything higher

powers of 5: 1/5 never seen 1/25, etc.

powers of 6: 1/6 never seen 1/36, etc.

powers of 12: 1/12 never seen 1/144 etc.

powers of 3: 1/3 never seen 1/9 etc.

That leaves powers of 7, 11, 13, and more primes.

Can anybody contribute other possible common fractions which are used in the
world today?

Again, I do have a valid reason for asking and which relates to gnucash
directly.