Quadratic residues are an important concept in number theory.

The quadratic residue is an important concept in number theory.

The love quadrangle between John, Mary, Sarah, and David became more complicated as they all developed feelings for each other.

I have four quadruple whole notes in my music sheet.

I need a quadruple whole note for this music piece.

A Pythagorean quadruple consists of four positive integers a, b, c, and d such that a^2 + b^2 + c^2 = d^2.

The graph is divided into four-quadrant.

I went quadbiking in the desert.

Quadratic formulae are used to solve quadratic equations.

Quadragesima Sunday is a significant day in the Christian calendar.