A number line is a ruler with nothing being measured on it.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
The number is a distance
The 7 on a number line marks the point that is 7 units away from 0.
Different from Grade 1
In Grade 1 numbers sat inside squares. Here they sit on marks, and the space between marks is the amount.
So count the spaces you move, not the marks you pass.
A ruler with nothing on it
Take the object away from the ruler and what is left is a line with equally spaced numbers. That is a number line. Everything you learned about reading a ruler — start at 0, count the spaces not the marks — applies to it unchanged.
Count the spaces, not the marks
From 0 to 5 there are six marks but only five spaces. The number tells you how many spaces you have travelled. Counting marks instead of spaces gives an answer one too big — this is the single most common number line error and it is worth checking for every time.
The spaces must be equal
A number line only works if every space is the same size. If someone draws 0, 1, 2 close together and then 3 far away, the picture lies about the distances. When you draw your own, use the squares on your paper to keep the spacing even.
Step 2: Try It Yourself
Move the start and watch where the dot lands.
7
Step 3: Watch an Example
One step at a time.
Watch Ana Find a Number
Ana is asked to find 12 on a number line marked every 5.
- Step 1
She finds the 10, which is labelled.
Step 4: Your Turn
Practice makes it stick.
Reading the Line
Problem 1 of 2
A dot sits three spaces past the 15 mark. What number is it on?
Back From Twenty
Problem 2 of 2
A dot sits four spaces before the 20 mark. What number is it on?
Where Does It Sit?
1 of 3
Two spaces past 10 is which number?
2 of 3
One space before 15 is which number?
3 of 3
How far is the 9 mark from 0?
Step 5: Quick Check
Show what you know.
Question 1 of 2
How far is 13 from 0 on a number line?
Question 2 of 2
On a number line, what should you count?
What You Learned
- A number line is a ruler with nothing on it.
- A number marks its distance from 0.
- Count the spaces you move, not the marks you pass.