Interactive coordinates grid

What the interactive coordinates grid does on screen

A numbered grid across the board, axes in navy, numbered as often as the range allows: every line to 10, every second one to 20, every tenth to 100. You tap to plot, and one bar of buttons does the reflecting, rotating and moving. The image travels to where it lands over about half a second, so the class watches the move happen, and a line under the grid says in words what it was.

• The grid, in one press. 0 to 10, 0 to 20 or 0 to 100 sets the lines and the numbers together. 1 quad, 2 quads and All 4 decide how much of it is negative, and the plus and minus buttons beside x and y stretch each axis on its own, so the grid can be a wide rectangle that uses the width of the board. Hold one down and it keeps going. The squares stay square, and whatever is plotted survives the change unless it falls off the new grid.
• Shape and Points. In Shape mode each tap joins on to the last, labelled A, B, C. In Points mode each tap drops a single labelled dot, and tapping it again removes it. Drag any point and the shape follows it, with the caption reading out where it has got to.
• Coords and Hide numbers. Coords writes the pair beside every point, blue for the original and red for the image; turn it off for a plainer picture. Hide numbers strips the numbers off both axes, which turns the board into a fill-in-the-labels question.
• Close, Undo and Clear. Close joins the last point back to A and fills the shape. Undo takes off the last point. Clear empties the grid.
• Reflect. Four buttons: the x-axis, the y-axis, y = x and y = −x. The mirror is drawn dashed in red, so the class can check the distance either side of it.
• Your own mirror line. Type a number into Mirror and press x= or y=. The line is drawn where you asked and the image lands the right distance beyond it.
• Rotate. 90 degrees either way or 180 degrees, always about the origin, ringed in purple while the image is showing.
• Move. Two boxes and a Go button translate the shape by the amounts you type, negatives included, and the caption reads it back in brackets.
• Clear img and Print. Clear img takes the red image away and leaves the original. Print gives you one A4 landscape sheet of the grid as it stands.

How to use it in a lesson

Plot slowly. The temptation on a board this size is to build a decagon, and then nobody can follow which point went where. Three or four points is plenty, and the letters do the rest of the work.

1. Start in one quadrant. Points mode, and call out coordinates for children to come and tap. Wrong taps are useful, so let them happen.
2. Switch to Shape and build a triangle. Ask for the three pairs of coordinates before you press Close, and write them up beside the grid.
3. Predict before every transformation. Ask where A will end up and get a pair of numbers, not a wave of the hand. Then press the button.
4. Read the caption together. It gives the class the exact wording of the answer, which is half the marks in a transformation question.
5. Compare the coordinates, not just the picture. A at (3, 5) becomes A prime at (3, −5). Which number changed, and why did the other not?
6. Open it out to four quadrants and do the same shape again, then Print if it is worth keeping.

Ideas by year group

• Year 1. 1 quad, Points mode. Not coordinates yet, just position words. Tap a dot and ask who can describe it well enough for a partner to find.
• Year 2. 1 quad, Points. Plot a dot and read the two numbers off the axes together. Along the corridor, then up the stairs.
• Year 3. 1 quad, Shape. Plot three corners of a square and ask the class for the fourth before anyone taps it.
• Year 4. 1 quad, Shape, then Move by (3, 2). Which coordinates changed, and by how much?
• Year 5. 2 quads. Reflect in the y-axis, then in a typed line like x = 2, and ask why the second lands somewhere different.
• Year 6. All 4. Rotate 90 degrees clockwise about the origin, then again, and ask what single turn would have done both.

The misconceptions it helps with

Reading the pair the wrong way round. (3, 5) and (5, 3) are different places. The labels print the coordinates next to the dot, so a child who taps the wrong one sees their own answer written on the grid rather than being told they are wrong.

Thinking a reflection just means the other side of the grid. Reflect in a typed line like x = 2 and the image lands two squares beyond that line, not over by the edge. The dashed mirror makes the distance the thing to check.

Losing the centre of rotation. Children turn a shape around itself rather than around a point. The purple ring at the origin gives the turn somewhere to happen, and 180 degrees sends a shape into the opposite quadrant, which always surprises somebody.

Counting the starting square as a move. Translate by (3, 2) and compare before and after. A at (4, 1) became A prime at (7, 3), so the count is three, not four.

Frequently asked questions