> ¼₀₀ {vulgar fraction one quarter}{subscript zero}{subscript zero} is the wrong way of writing this, generally producing a suboptimal result (denominators and

> ¼₀₀ {vulgar fraction one quarter}{subscript zero}{subscript zero} is the wrong way of writing this, generally producing a suboptimal result (denominators and subscripts occupy different lines, and the known fractions often have slightly different, more manually-optimised layouts anyway). The proper way is {digit one}{fraction slash}{digit four}{digit zero}{digit zero}: 1⁄400. Won’t render looking like a fraction with split numerator and denominator in all fonts, but it should mostly look better.