First Quadrant Coordinates
Describe positions on a 2-D grid as coordinates in the first quadrant
What a learner can do afterwards
- Read the coordinates of a point on a grid as (3, 5)
- Explain that the first number is the horizontal distance and the second is the vertical distance
- Identify the coordinates of all vertices of a shape plotted on a grid
- Use two coordinates on the same grid line to find a side length or the middle of an edge, such as the bottom side from (1, 1) to (6, 1)
1 · Read
A grid is a flat space covered in crossing lines that make little squares. You can point to any spot on the grid using just two numbers, so you can tell a friend where treasure hides on a map. Those two numbers are called coordinates: across first, then up. The across number is also called the x-coordinate, and the up number is the y-coordinate.
Ravi is playing a treasure map game. The treasure is 4 steps across and 3 steps up from the corner of the map. Ravi writes this as the coordinates (4, 3): first the across number, then the up number. The corner where counting starts is (0, 0).
From (2, 1) to (8, 1), the side length is 8 minus 2 = 6 squares. Halfway between 2 and 8 is 5, giving midpoint (5, 1). For an upright side, subtract the up numbers instead.
Both ends share the up number 1. The middle sits halfway along, at (5, 1).
Always read the numbers in order: across first, then up. If you say them backwards, you can point to the wrong spot.
Coordinates name a spot with two numbers: across first, then up.
2 · Watch
Take it off screen
Where it sits
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
18 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.