Measuring Length
Learn
What is Length?
Length is how long something is from one end to the other. We measure length to find out how big or small things are!
Ways to Measure
We can measure length using different things:
Measuring Tools
- Non-standard units - Things like paper clips, blocks, crayons, or your hand
- Standard units - Rulers measure in inches or centimeters
How to Measure with Objects
You can use small objects to measure bigger things. Here's how:
- Line up your measuring objects in a row (no gaps, no overlaps!)
- Start at one end of the thing you are measuring
- Stop at the other end
- Count how many objects you used
Important Rule!
When measuring, make sure there are NO GAPS between your measuring objects and NO OVERLAPS. They should touch end to end!
Using a Ruler
A ruler has numbers that show inches or centimeters. To use a ruler:
- Put the object at the 0 (or the very edge of the ruler)
- Look at where the object ends
- Read the number - that's the length!
Examples
Let's practice measuring!
Example 1: Measuring a pencil with paper clips
Step 1: Line up paper clips along the pencil
Step 2: Make sure there are no gaps or overlaps
Step 3: Count the paper clips: 1, 2, 3, 4, 5, 6
Answer: The pencil is 6 paper clips long
Example 2: Measuring a book with cubes
Step 1: Line up cubes along the side of the book
Step 2: No gaps, no overlaps!
Step 3: Count: 1, 2, 3, 4, 5, 6, 7, 8
Answer: The book is 8 cubes long
Example 3: Measuring a crayon with a ruler
Step 1: Put the crayon at 0 on the ruler
Step 2: Look at where the crayon ends
Step 3: It ends at 4
Answer: The crayon is 4 inches long
Example 4: Measuring your desk with hand spans
Step 1: Spread your hand wide (thumb to pinky)
Step 2: Put your hand at one end of the desk
Step 3: Move and count: 1, 2, 3, 4, 5 hands
Answer: The desk is about 5 hand spans long
Example 5: Measuring a marker with a ruler
Step 1: Line up the marker at 0
Step 2: The marker ends at 5
Answer: The marker is 5 inches long
Practice Problems
Try these measuring problems!
1. A ribbon is 7 paper clips long. How many paper clips did you use to measure it?
Show Answer
7 paper clips were used to measure the ribbon.
2. A toy car on a ruler starts at 0 and ends at 3. How long is the car?
Show Answer
The car is 3 inches long.
3. You measure a book with cubes. You use 10 cubes. How long is the book?
Show Answer
The book is 10 cubes long.
4. A straw on a ruler ends at 6. How long is the straw?
Show Answer
The straw is 6 inches long.
5. You measure your shoe with your thumb. It takes 8 thumbs. How long is your shoe?
Show Answer
Your shoe is 8 thumbs long.
6. A string takes 4 crayons to measure. How long is the string?
Show Answer
The string is 4 crayons long.
7. Your pencil on a ruler goes from 0 to 7. How many inches is it?
Show Answer
The pencil is 7 inches long.
8. A stick is 12 cubes long. Is that longer or shorter than 10 cubes?
Show Answer
12 cubes is longer than 10 cubes.
9. You measure a table. It is 15 hand spans. Your friend says it is 14 hand spans. Why might you get different answers?
Show Answer
Your hands might be different sizes! Bigger hands = fewer hand spans. Smaller hands = more hand spans.
10. An eraser on a ruler ends at 2. How long is the eraser?
Show Answer
The eraser is 2 inches long.
Check Your Understanding
Answer these questions about measuring!
1. What should you NOT have when lining up objects to measure? (Hint: two things!)
Show Answer
You should not have gaps or overlaps between your measuring objects.
2. Where should you start when measuring with a ruler?
Show Answer
Start at 0 (or the very edge of the ruler).
3. Why might two people get different measurements for the same object using paper clips?
Show Answer
They might use different sized paper clips, or one person might have gaps or overlaps.
4. Name two things you could use to measure your desk.
Show Answer
You could use a ruler, paper clips, cubes, crayons, hand spans, or many other things!
Next Steps
- Practice measuring things around your house
- Try using different objects to measure the same thing
- When you are ready, move on to Comparing Lengths
- You are becoming a measurement expert!