Reading a Metric Ruler - Grade 3
A worksheet for 3rd graders to practice reading and understanding metric rulers, measuring lengths in centimeters and millimeters.
Includes
Standards
Topics
Reading a Metric Ruler
Name:
Date:
Score:
Read each question carefully and follow the instructions. Use the ruler to measure the objects or answer the questions about the ruler.
Understanding Centimeters (cm)
Look at the ruler below. Each big number marks 1 centimeter (cm).

1. How many centimeters are shown on this ruler?
2. Circle the number that shows 5 cm.
3
5
10
1
Centimeters and Millimeters (mm)
Each small line between the centimeter marks is 1 millimeter (mm). There are 10 millimeters in 1 centimeter.
3. 1 cm = mm
4. 3 cm = mm
5. A pencil is 12 cm long. How many millimeters is that? mm
Measuring Objects
Imagine you are measuring these objects with a metric ruler. Write down their lengths.
6. A paperclip is approximately 3 cm long. How many millimeters is this?
7. A crayon is approximately 70 mm long. How many centimeters is this?
True or False
8. There are 100 millimeters in 1 centimeter.
True
False
9. A ruler often measures in centimeters and inches.
True
False