distributing numbers

[Neil]

Hello,

I need some help coming up with an equation, or finding an existing one that
would work.

example:
123
-
-
789

I would like to find 2 numbers (-) that are evenly distributed between the
numbers 123 and 789.

thanks!

 

[Barb R.]

If

A1=123
A2=789

A3=A1+(A2-A1)/3
A4=A1+2*(A2-A1)/3