$\frac{ 4{x}^{2}{y}^{2} \times \left( 1-2xy \right) }{ 4{x}^{2}{y}^{2} }$
Cancel out the common factor $4$$\frac{ {x}^{2}{y}^{2} \times \left( 1-2xy \right) }{ {x}^{2}{y}^{2} }$
Cancel out the common factor ${x}^{2}$$\frac{ {y}^{2} \times \left( 1-2xy \right) }{ {y}^{2} }$
Cancel out the common factor ${y}^{2}$$1-2xy$