Teaching the Common Core Math Standards With Hands-On Activities, Grades 3-5 (91 page)

Closure

Discuss the points students plotted. Ask for volunteers to use the overhead projector to find the points they plotted in the coordinate plane. Ask students to write the coordinates of four points of their own, then exchange their points for the points of a classmate. Students are to plot these points in their own coordinate planes, then check each other's work.

Directions for Constructing a Coordinate Plane

Follow these steps to construct a coordinate plane.

1.
Find two perpendicular lines that intersect at or near the center of your graph paper. Using your ruler, draw two perpendicular lines on these lines. Put arrowheads at both ends of each line to show that the lines go on infinitely.

2.
Mark the point at which the lines intersect with a dot. This point is called the origin. Label this point (0, 0).

3.
Starting at the origin, move to the right. Number the first 10 vertical lines on your graph paper 1 through 10. Starting at the origin again, move to the left. Number the first 10 vertical lines on your graph paper
through
. The horizontal line you moved along is called the
-axis.

4.
Starting at the origin, move upward. Number the first 10 horizontal lines on your graph paper 1 through 10. Starting at the origin again, move downward. Number the first 10 horizontal lines on your graph paper
through
. The vertical line you moved along is called the
-axis.

5.
Points are always identified by two coordinates, for example, (3, 4). The first coordinate is the
-coordinate. It is plotted by moving along the
-axis. The second coordinate is the
-coordinate. It is plotted from the
-coordinate by moving along the
-axis or on a line parallel to the
-axis. Following are two examples:

• To plot point (3, 4), start at the origin. Move 3 units to the right along the
  -axis. Now move 4 units up, parallel to the
  -axis. Mark this point and label it (3, 4).
  
• To plot point
  , start at the origin. Move 1 unit to the left along the
  -axis. Now move 5 units down, parallel to the
  -axis. Mark this point and label it (
  ).