The order in which you write x- and y-coordinates in an ordered pair is very important. The x-coordinate always comes first, followed by the y-coordinate. As you can see in the coordinate grid below, the ordered pairs (3,4) and (4,3) are two different points!
What is the first coordinate?
The first coordinate (usually the x-coordinate) is called the domain and the second (usually the y-coordinate) is called the range.
What order is coordinates in?
Coordinates are ordered pairs of numbers; the first number number indicates the point on the x axis and the second the point on the y axis. When reading or plotting coordinates you always go across first and then up (a good way to remember this is: 'across the landing and up the stairs').