Measurement

Measurement of length

Length

Length is a measure of how long an object is. Different lengths are measured in different units.

In our daily lives, we measure the lengths of many different items. In the past, lengths were measured by the width of fingers, hands, arms, or steps. The lengths, however, vary from person to person. Therefore, these are not measurements in standard units

For example, children estimate a desk’s length to be five hand spans. A different student, however, measured it at six hand spans. Hand span is not a standard measurement, however. Standard units of length are “metres,” which are precise and practical for everyone. We use a smaller unit to measure tiny items like pencils, books, and other items.

We use metres to measure the length of big objects, like the length of a piece of cloth, the length of the room, a field or street, etc. Students use a ruler scale to measure length, whereas a cloth merchant uses a metre rod. and tailors use metre tape. To measure the length of a pencil with a ruler scale Put one end of the pencil at 0 mark of the ruler scale. Read the mark at the other end of the pencil.

The length of the pencil is 8 cm

 Try measuring your eraser with a ruler

The length of my eraser is ____ cm

Converting metres to centimetres

Addition and Subtraction of length

Addition of length

Example: 5 m 78 cm + 3 m 20 cm.

Solution:

Subtraction of length

Example: 12 m 54 cm - 4 m 54 cm.

Solution: