Number Line
A number line is a straight line with equally spaced ticks, each labelled with a number. Set the start, the end and the step, how often to label the ticks, how many lines you want on the page and whether to leave the labels blank, and the sheet is drawn for you.
Your sheet
Printing: choose Actual size or 100%, not “Fit to page”, so 1 cm prints as 1 cm. How to check.
How are the ticks placed?
Ticks = (end − start) ÷ step + 1, spread evenly between the two ends of the line. Tick k is labelled start + k × step.
Worked example. 0 to 20 in steps of 1: (20 − 0) ÷ 1 + 1 = 21 ticks. On A4 portrait the line is 166 mm long, so the ticks are 8.3 mm apart. 0 to 100 in steps of 10 gives 11 ticks, 16.6 mm apart. Every label is the exact value, with floating-point drift removed, so 0.1 + 0.2 shows as 0.3.
Adding and subtracting on a number line
Start at the first number and jump right to add, left to subtract. 8 + 5: start at 8, jump 2 to 10 and 3 more to 13. Drawing the jumps as arcs above the line makes the method visible, which is why a blank line with room above it is the classroom favourite.
Number lines for fractions and decimals
A line from 0 to 1 in tenths shows that 0.5 is half way; a line from 0 to 2 in quarters shows 1¼, 1½ and 1¾ beyond 1. Printing both on one page, one above the other, links the two notations.
Number lines for scale and measurement
A line from 0 to 100 in tens is a percentage bar. A line from -10 to 30 in fives is a thermometer. A line from 0 to 60 in fives is a minute scale for telling the time. The printable ruler is a number line at true size.
Questions about number lines
What number line should I print for a young child?
0 to 10 or 0 to 20 in steps of 1, with every tick labelled: 21 ticks for 0 to 20. Six lines on a page gives one for each sum in a short exercise.
How do I make a number line with negative numbers?
Set the start to -10 and the end to 10, step 1: 21 ticks with 0 in the middle. For temperatures, try -20 to 40 in steps of 5 and label every 2nd tick.
Can I make a fraction or decimal number line?
Yes. For quarters, set the step to 0.25 from 0 to 2 and label every tick, or every 4th to label whole numbers only. For tenths, step 0.1 from 0 to 1. Labels are shown as decimals.
What is a blank number line?
A line with ticks but only the two end numbers labelled, so the child fills in the rest. Tick “Blank labels”. It is also the sheet for showing jumps in addition and subtraction, where you write only the numbers you land on.
How many ticks can a line have?
Up to 201 (200 steps). Labels shrink as ticks get closer, so for 0 to 100 in ones label every 5th or 10th tick. 0 to 100 in tens has only 11 ticks and labels well.