A number line is defined as a straight line with numbers placed at equal segments or intervals along its length. The numbers on the number line increase as one moves to the right and decreases as one moves to the left.
Number Line Terms Video
This fun video song explains number line terms.
Living Number Line (Thinking of a Number)
Note: Some of these activities are appropriate for preschool and kindergarten students who are learning about numbers. For this age group, keep it simple and only use 0-5 or 0-10.
Create individuals cards each with one character: 0-10, A, B, Greater than, Less than and Equals. Give one number card to 11 students and have them line up in order. Secretly, choose a number. Ask students to guess the number. If the guess is incorrect, tell the student if the correct number is greater than or less than the guessed number. The student who guesses correctly is given the A card and should stand in front of the corresponding number. (Example: If the correct number is 4, the student who guessed 4 will hold the A sign in front of the student who is holding the 4 sign.) Repeat with a second number. Finally, ask a student to determine if A is greater than or less than B. That student will stand between A and B, holding the corresponding card.
Modification: When standing in line, have students count off. (Can have all the students count or only the first 11 students.) Ask a student to be "A" and another student to be "B". Give A a number to stand beside (or let A choose a number). Give B a number to stand beside (Is A greater or less than B?) or ask B to stand where he is greater or less than A.
If learning about negative numbers, count off -10 to zero to 10. The negative numbers face to the left, zero faces forward and the positive numbers face to the right. Repeat plotting A and B along with greater than and less than.
Plotting Halfway between Two Numbers
Dive deeper into math concepts using number lines. These activities make great warm-up activities or exit activities!
Number lines can be used to help teach additional math concepts. What is halfway between 1 and 5? Many students will subtract 1 from 5 to get 4; then divide 4 in half to get the answer 2. Use a number line to demonstrate how to determine the real answer - 3. Plot the numbers 1 and 5 and then the student's answer of 2. Does 2 look like it is halfway between 1 and 5? Try this again with bigger numbers: 100 and 500 or 1,000 and 5,000. Then try harder numbers! Plot the halfway mark when one given number is a negative number. Create a tactile line (without tick marks) with only two numbers on it. Put a mystery tick mark halfway between these two numbers. What is the mystery number?
Where Does this Number Belong?
Critical thinking is an important math skill! Start with a number line (without tick marks) and the point 0 marked on the far left side and the point 4,000 marked on the far right side. Where would 1,000 be on this number line? Where would 1,000 be on a number line that is marked 0 to 2,000? Can you visualize the different locations? Ask the student to justify - in writing - how he determines his answer.
Have a number line with 0 on the far right, 200 (at about the second tick mark, if there were tick marks) and ask where 1,000 would go on this number line. Ask the student to justify your answer.
Number Lines and O&M
For students who are visually impaired, being able to "visualize" the number line and the relationships of the marks/numbers on the number line is not only an important math skills but also a functional O&M skill! Relate the number lines to points along a route. Example: The hall starts at the gym and ends at the office. What room is halfway down the hall? The music room is 3/4ths of the way down the hall. Can your student visualize these points? How about comparing one block on his street and associating each house with a tick mark on a number line. Where his house is in on that block? How about several blocks in his neighborhood. Where is McDonald's in relationship to these blocks?
Cork Board Number Line
Use a cork board and push pins to create tactile number lines on the go! (This is a great alternative when the class is using individual dry erase boards to do quick number line activities!) Depending on the activity, a generic braille number line can be added to the cork board and students use different types of push pins to plot A and B, etc. The generic number line may have just the line and arrows or any combination of line, arrow, tick marks, numbers and plotted points. The student may use smaller pins to add his own tick marks. Students can also "pin" braille numbers to label the number line. Be creative!
Additional Number Line Questions
Ask these questions (or turn the question into a warm-up activity!) Ask your student to explain their thought process!
- Do you always start at 0?
- Find the missing numbers in all different places along the number including BEFORE the first number listed, AFTER the last number listed or between tick marks
- Explain why number lines have arrows on the end?
- Create a number line with different intervals (2's, 5's, 7's)
- Plot points on a number line - including between tick marks
- Identify points that YOU plotted - be creative!
Example: Number line with only two tick marks - one on the far left (400) and one on the far right (1,000). Place a tick mark 3/4ths between the two numbers. "What number do you think is marked in this number line? Explain your thinking."