Depending on the type of equation, a slash (acting as a division sign) can be used to separate the parts of the fraction. Although the slash normally does not have space inserted around it, a thin space or hairspace may be needed to make the fraction look visually balanced, depending on the particular characters on either side and the font used; it may be possible to use a dedicated equation editor to automatically adjust the spacing:
a + b/c [with no space added]
a + b /c [with a thin space added before the slash]
\(a + b/c\) [using an equation editor]
(This also shows that equations entered using an equation editor often have a different ‘look’ from those entered manually. Establishing an overall policy on how mathematical material is to be written can be a good idea.)
Fractions can be built up using a horizontal line to indicate the division sign (‘display’ format):
\[a+\frac{b}{c}\]
