Formula layout
From Apache OpenOffice Wiki
The most difficult part of using OOoMath comes when writing complicated equations. This section provides some advice about writing complex formulas.
Brackets are your friends
OOoMath knows nothing about order of operation. You must use brackets to state order of operations explicitly. Consider the following example:
Markup  Result 

2 over x + 1  
2 over {x + 1} 
Equations over more than one line
Suppose you want to type an equation covering more than one line. For example:
Your first reaction would be to simply press the Enter key. However, if you press the Enter key, though the markup goes to a new line, the resulting equation does not. You must type the newline command explicitly. This is illustrated in the table below.
Markup  Result 

x = 3 y = 1 

x = 3 newline y = 1 
