Mod Command

Mod( <Dividend Number>, <Divisor Number> )

Yields the remainder when dividend number is divided by divisor number.

Mod(9, 4) yields 1.

Mod( <Dividend Polynomial>, <Divisor Polynomial> )

Yields the remainder when the dividend polynomial is divided by the divisor polynomial.

Mod(x^3 + x^2 + x + 6, x^2 - 3) yields 4 x + 9.

If you want a function to do this, you can define it yourself, e.g. mod(x, y) = y (x / y - floor(x / y)).