Length in centimetres and millimeters
For smaller objects, we use centimetres and millimetres to measure the length.
Example 2: Anam wants to measure the length of her pencil. She can use a ruler to measure the length.
The pencil is 8 centimetre long. We can also write it as 8 cm
Look at your ruler.
There are 10 equal parts between 0 cm and 1 cm on the ruler. Each part is 1 millimetre long. We can also write if as 1 mm.
So, there are 10 mm in 1 cm.
1 cm = 10 mm
Ali measures the length of his eraser
The eraser is 1 cm long
We can also say that the eraser is 10 mm long
We also use millimetres to measure objects that are small or not exactly at the centimetre mark on the rular
The length of the nail is between 5 cm and 6 cm.
We can see that it is 3 mm longer than 5 cm.
So, length of the nail is 5 cm 3 mm.
We can also write this length in millimetres
5 cm 3 mm = 5 cm + 3 mm 5 cm
= 50 mm + 3 mm
= 53 mm
The length of the nail is 53 mm
Sara measures the length of a chalk. The chalk is 15 mm long. Can you write it in centimetres and millimetres?
15 mm = 10 mm + 5 mm
= 1 cm + 5 mm
= 1 cm 5 mm
The length of the chalk is 1 cm 5 mm