FractionalPart Function

fractionalPart( <Expression> )
Returns the fractional part of the expression.
Examples:
• fractionalPart( 6 / 5 ) yields \frac{1}{5} in CAS View, 0.2 in Algebra View.
• fractionalPart( 1/5 + 3/2 + 2 ) yields \frac{7}{10} in CAS View, 0.7 in Algebra View.
Note:

In Mathematics fractional part function is defined sometimes as

x-\lfloor x\rfloor

In other cases as

sgn(x)(\mid x\mid-\lfloor \mid x\mid\rfloor) .

GeoGebra uses the second definition (also used by Mathematica).
To obtain the first function you may use f(x) = x - floor(x)