Outside the US, short lengths are measured in centimeters. Your finger is about 1 cm wide.
Centimeter is a small unit of length. It is written cm.
Step 1: Let's Learn
Read it, or press Listen and follow the words.
A meter is a hundred
100 centimeters make 1 meter. A door is about 2 meters tall. You are about 1 meter and a bit.
Start at zero
Put the end of the thing on the 0 of the ruler. Read the number at the other end.
The American word
In the US, people measure in inches. An inch is longer than a centimeter. About two and a half centimeters make one inch. Many rulers show both.
Step 2: Try It Yourself
Centimeters on top. Inches underneath.
centimetres
051015202530
inches
0510
It starts at 0 and ends at 12, so it is 12 centimetres long.
The same object is about 4.7 inches. Inches are bigger, so it takes fewer of them.
Me
120
Door
200
Door is 80 centimeters longer than Me.
Step 3: In Real Life
The door frame at home
A pencil mark on the door frame says 118 cm. Next birthday the mark is at 124 cm. Six centimeters taller. The tape measure did the counting.
Step 4: Watch an Example
One step at a time.
Watch Mia Measure Her Book
Mia puts her book on a ruler.
- Step 1
She lines the edge up with 0.
Step 5: Your Turn
Practice makes it stick.
The Door Frame
Problem 1 of 2
How many centimeters make a meter?
cm
Two Rulers
Problem 2 of 2
Which is longer, one inch or one centimeter?
Centimeters and Meters
1 of 3
A pencil is 12 cm. A crayon is 8 cm. How many cm longer is the pencil?
2 of 3
Two meters. How many centimeters?
3 of 3
Ravi is 110 cm. His sister is 100 cm. How many cm taller is Ravi?
Step 6: Quick Check
Show what you know.
Question 1 of 2
Where does the end of the thing go on the ruler?
Question 2 of 2
About how many centimeters is a door tall?
What You Learned
- Short lengths are in centimeters.
- 100 cm make a meter.
- Inches are the American unit, and longer than a centimeter.
For the grown-up
This course is for families outside the United States. Grade 2 Math teaches centimeters and inches together; here the child meets centimeters as their own unit and inches as the American one they will see in books.
Measure the child on a door frame in centimeters and date the mark. Height is the measurement a child cares about, and a growing mark teaches subtraction without a worksheet.