1. Spell out and hyphenate fractions that are less than one as in three-quarters.

2. Write fractions attached to a number with one space after the number as in 2 1/4. (Note: do not use superscript, i.e., 2¼. )

3. Do not mix fractions and decimals as in from 2 1/4 to 2.75 percent

 

Source
Dragoman Style Guide for Figures