Interactive number line for the whiteboard

What the interactive number line does on screen

It draws one number line across the whiteboard, with the controls a lesson actually needs along the top and bottom: the range, the labels, a pointer you can drag, markers and counting hops. Everything is one press, so you can change it while you are talking.

• Range. The Range pill opens 22 lines in four groups: whole numbers from 0 to 10 up to 0 to 1,000,000; below zero; tenths and hundredths; and 0 to 1 in halves, thirds, quarters, fifths, eighths and tenths, labelled as simplified fractions, so two quarters is written as one half.
• Your own line. From, To and Label every take minus numbers, decimals and typed fractions, and apply on Enter. Divisions sets the small ticks between two labels, so 0 to 1 labelled every 0.1 with ten divisions gives you hundredths.
• The pointer. Tap or drag anywhere and the yellow arrow goes there with its number on top. It reads every whole number as it moves, whatever the labels say, so a line labelled every 10 still tells you 47. Snap switches between stepping tick by tick and sliding freely, and Hide value covers its number.
• Markers. Marker + pins a coloured flag at the arrow, up to six, each draggable and each with a small x. Difference brackets the gap between the last two and writes the answer underneath.
• Hiding numbers. Tap any number to turn it into a question mark, and tap it again to bring it back. Hide middle leaves only the two ends, Hide all blanks the lot, Blanks hides a few at random.
• Hops. Set a Jump size and press Hop + or Hop −. An arc is drawn from where the arrow was to where it lands, labelled with the amount.
• Empty line, Clear, Reset and Print. Empty line leaves a bare arrowed line to write on with the pen, Clear takes off the markers and hops, Reset goes back to 0 to 100, and Print gives you one A4 landscape picture of the board as it looks.

How to use it in a lesson

Set the line up before the children are looking at it, then do one thing with it. A number line doing three jobs at once turns into decoration.

1. Pick the range first. Take the nearest ready-made line, or type your own From and To and press Enter. Changing the range keeps whatever still fits, so a marker on 20 survives a move from 0 to 100 down to 0 to 50.
2. Set Label every and Divisions. Fewer labels is usually better. Labelled every 10 with ten divisions, a 0 to 100 line has nine unlabelled numbers between every pair, and that is where the thinking is.
3. Drag the arrow and ask where it is. Turn Hide value on first and take three answers before you reveal anything. The disagreement is the lesson.
4. Pin a marker on each answer worth keeping. Two markers and Difference turns any pair of numbers into a subtraction the class can see.
5. Hop along it. Type the step into Jump size and press Hop +. Ask what the next arc will look like before you draw it.
6. Hide the numbers and go back over it, then Print the board if you want the same line on paper for the ones who need it in front of them.

Ideas by year group

• Year 1. 0 to 10 or 0 to 20, labelled every 1. Hide all, then count along together and tap each question mark as you say it.
• Year 2. 0 to 100 labelled every 10. Drag the arrow to 47 with Hide value on and ask which ten it is nearest, then which ten it is between.
• Year 3. 0 to 1000 labelled every 100. Hop in hundreds from 250 and watch which digit changes, then hop back.
• Year 4. -20 to 20. Start on 8, hop back 15, and ask which is colder, -3 or -7. Then put a marker on each and press Difference.
• Year 5. 0 to 1 in tenths with ten divisions. Where does 0.35 go? Is it the same place as 0.350?
• Year 6. 0 to 1 in eighths, then switch the range to tenths. Put markers on three eighths and on 0.375 and show they land together.

The misconceptions it helps with

Counting the ticks instead of the jumps. A child going from 4 to 7 says four, five, six, seven and gets four. The drawn arc makes the jump the thing being counted.

Thinking numbers only exist where the labels are. Drag the arrow into a gap on a line labelled every 10 and it tells you 47. Nine numbers were hiding between every pair, and that is usually news.

Reading a decimal as a whole number. On a 0 to 1 line, 0.5 and 0.50 land in the same spot and 0.35 sits in the middle rather than near the end. Seeing that is quicker than explaining it.

Bigger digit, bigger number. Set the range to -20 to 20 and zero sits in the middle, so -7 is plainly further left than -3.

Frequently asked questions