Idea 1of 13
Across, then up
How do two numbers say exactly where a point is?
Today you'll discover
- where to start counting
- which number comes first
- how to write a point's coordinates
Think firstPoint A is somewhere on the grid
How far across from 0 is point A?
Decide first, then press Next. Put your finger on 0 and count along the bottom first.
A square grid numbered 0 to 15 along the bottom and up the left side, with point A marked. An orange line runs along the bottom from 0 to 6, then a blue line rises from 6 up to A at 12. Beside the grid, A is written as (6, 12). The last step shows seven points and asks for C.
See the whole ideathe big idea and the key word, in one place
The big idea
A point's coordinates are (across, up), both counted from 0.
Easy to get wrong(6, 12) and (12, 6) are different points. Swap the two numbers and you land somewhere else on the grid.
Key words
- coordinates
- the two numbers that say where a point is: (across, up)
- origin
- the corner where counting starts, at (0, 0)
- x-axis
- the number line along the bottom: how far across
- y-axis
- the number line up the side: how far up
Ready to use it?
- Write the coordinates of a point on a grid.
- Plot a point from its coordinates.