EXPLORE
1
3
A number line is a way to show numbers in order, from the smallest to the largest.
Writing numbers on a number line makes it easier to compare, add or subtract numbers.
Math Grade 2
What is a Number Line?
1
3
The numbers on the number line are listed in order from left to right like on a ruler.
Each number represents a length from 0. The line is called a tick.
A dot, called a point, on the number line represents a specific number.
Math Grade 2
Parts of a Number Line
What number does this point represent?
1
3
Let's look at the number line below.
Math Grade 2
Representing Numbers
Each tick mark represents a number. You can use the number line to add or subtract numbers by counting back or counting forward.
Count forward
Count back
3
1
Let’s add 4 + 3
Step 1: We begin at the number 4 on our number line.
Step 2: To add 3, we need to move to the right.
Each step is like adding one number.
How many steps should we take to add 4 + 3?
Math Grade 2
Adding Numbers on the Number line
1
2
3
4+3=?
3
1
Math Grade 2
Number lines that represent addition
Let’s look at the number line below.
What addition equation is represented by this number line?
How do you know?
+ =
3
1
Math Grade 2
Subtracting Numbers on the Number line
Let’s subtract 10 - 4
Step 1: We begin at the number 10 on our number line.
Step 2: To subtract 4, we need to move to the left.
Each step is like subtracting one number.
How many steps should we take to subtract 4 from 10?
1
2
3
4
10-4=?
3
1
Math Grade 2
Number lines that represent subtraction
Let’s look at the number line below.
What subtraction equation is represented by this number line?
How do you know?
- =
3
1
Math Grade 2
Let’s Review
A number line is a way to show numbers in order, from the smallest to the largest.
The numbers on the number line are listed in order from left to right.
Each number represents a length from 0. The line is called a tick.
A dot, called a point, on the number line represents a specific number.
To add we count moving forward and to subtract we count back.
PRACTICE