[Groff] Integer arithmetic

[Miklos Somogyi]

Hello, in real world this is sooo easy:

h = 105,5 mm
w = h *0.36

In groff world 105.5 and 0.36 needs to come in centimeters, then some  
correction needs to be applied.

Let's say that h is already done and contains roughly 300,000u.
The 0.36 may come as some 10,000 for 0.36c and some 28,000 for 1c with  
which we need to divide 0.36c

We have an  A * B / C thing to be executed either as (A * B) / C or  
(A / C) * B.
The first one may result in an overflow, the second may lose precision.

How do you handle similar problems? Divide B and C with 10? Or with  
100 before turning to, say, (A*B)/C?
One can spend too much time on things like this.

Miklos