Adding on a number line is a jump forward. Subtracting is a jump back.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
The size of the jump
The length of the arc is the number you are adding. Where you land is the answer.
Jump in tens first
To add 23, jump 20 and then 3. Two easy jumps beat twenty-three tiny ones.
The line keeps track of where you are, so you do not have to.
Direction carries the operation
On a number line, adding is a jump to the right and subtracting is a jump to the left. The size of the jump is the number you are adding or taking away. So 8 + 5 is: start at 8, jump 5 to the right, land on 13.
Big jumps beat little ones
You could add 5 as five jumps of 1, but one jump of 5 is faster and less error-prone. Better still, split it usefully: to add 5 to 8, jump 2 to reach 10, then jump 3 more. That is the make-ten strategy drawn as a picture.
The gap between two points
A number line also shows differences. To find 13 - 8, put a finger on 8 and one on 13 and count the spaces between them: 5. This is why subtraction and "how much longer" feel like the same question — on a number line they are the same picture.
Step 2: Try It Yourself
Change the jumps and read the equation underneath.
24 + 20 + 3 = 47
The round dot is where you started. The square is where you landed.
45 − 10 = 35
The round dot is where you started. The square is where you landed.
Step 3: Watch an Example
One step at a time.
Watch Leo Add on the Line
Leo works out 24 + 23 on a number line.
- Step 1
He starts at 24 and splits the 23 into 20 and 3.
Step 4: Your Turn
Practice makes it stick.
The Long Jump
Problem 1 of 2
Ana starts at 31 and jumps forward 20, then 5. Where does she land?
Going Back
Problem 2 of 2
Leo starts at 52 and jumps back 20. Where does he land?
Jump It Out
Jump the tens first, then the ones.
1 of 4
35 + 20 = ?
2 of 4
42 + 14 = ?
3 of 4
60 − 30 = ?
4 of 4
48 − 12 = ?
Step 5: Quick Check
Show what you know.
Question 1 of 2
Start at 26 and jump forward 20. Where do you land?
Question 2 of 2
Which way does a subtraction jump go?
What You Learned
- A forward jump adds. A backward jump takes away.
- Jump the tens first, then the ones.
- Where you land is the answer.