Length is a measure of how long something is. We use
rulers or tape to measure length.
We most of the time measure length in millimeters, centimeters
(cm), meters (m) and kilometers (km) as unit of length. Millimeters and centimeters
are used to measure short lengths. Long lengths are measured in meters.
The distance between two far off places is measured in kilometers (km)
length of a pencil is measured in centimeters, Length of bed in meters, while
the distance between two places is measured in kilometers.
- The standard unit of length is ‘Meter’.
- We use ‘cm’ for centimeter, ‘mm’ for millimeter, ‘m’
for meter and ‘km’ for kilometer in short form.
- 1 centimeter length is equally divided into 100 small
parts and each part is called millimeter (mm).
Thus, 1 cm = 100 mm or 100 mm = 1 cm
- 1 meter length is equally divided into 100 small parts
and each part is called centimeter (cm).
Thus, 1 m = 100 cm or 100 cm = 1 m
- 1 kilometer length is equally divided into 1000 small
parts and each part is called meter (m).
Thus, 1 km = 1000 m or 1000 m = 1 km
Addition and Subtraction of units of length
Arrange the number in column according to the units.
First add smaller unit then add larger unit.
A shopkeeper had 250m long rope. 190m was sold. What is
the length of the rope left?
Length of rope = 250m
Length of rope sold =190m
Length of rope left = 250m – 190m
convert meters into centimeters, we multiply the given number of meters by 100.
Example1: Convert 5m into cm
5m = 5 x 100
Convert 4m 85cm into cm
4m 85cm = 4 x 100cm + 85cm
400cm + 85 cm = 485 cm
convert kilometers into meters, we multiply the given number of kilometers by
Example1: Convert 15km into
15m = 15 x 1000
Convert 4km 850m into m
4km 850m =4 x 1000m + 850m
4000m + 850m