The Chicago Manual of Style Online 12.48: Multiple and multilevel fractions

12.46:
Fractions in display 12.47:
Fractions in subscripts and superscripts 12.48:
Multiple and multilevel fractions 12.49:
Rewriting fractions using exponents 12.50:
Matrices

12: Mathematics in Type

Chapter Contents» Style of Mathematical Expressions» Fractions

12.48Multiple and multilevel fractions

If a mathematical expression contains more than one fraction, it should be displayed, and the horizontal bar should be used for the principal fraction sign:

Fractions should preferably be limited to two levels:

Continued fractions, that is, expressions of the form a1 + 1/b1, where b1 = a2 + 1/b2, b2 = a3 + 1/b3, and so on, are displayed: