Multiplication of two even numbers always produces an even number, so x multiplied by 2 is even. Adding an odd number (y) to that even number always produces an odd number.
Vermenigvuldiging van twee ewe getalle gee altyd 'n ewe getal, dus is x maal 2 altyd 'n ewe getal. Die bytel van 'n onewe getal (y) by daardie ewe getal gee altyd 'n onewe getal.