fPart

On a TI calculator you can calculate the fractional part of a value

MATH ► 4

or via the catalog as

CATALOG ⎵

2nd 0 ►fPart( ENTER

To separate the fractional part of 85 / 4 = 21.25 which is 0.25

MATH ► 4 fPart( 8 5 ÷ 4 ENTER fPart(85/4

.25