Page 156 - Math Genius C2

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Standard Units of Length

To make our judgement more reliable and accurate, we should have a common set

of standard units of measurement. Scientists all over the world accepted a set of

standard units for the sake of uniformity.
The fixed measurements for measuring lengths are centimetres and metres.

Centimetre

This is a centimetre. We write centimetre as cm.
cm cm

Be Aware
We use the word ‘about’ to
show that the measurement
is not exact.
About 1 cm About 3 cm About 15 cm

We use a 15 cm or 30 cm ruler to measure shorter lengths.
Measuring Length Using a Ruler (Scale)

To measure the length of an object with a ruler, we follow these steps:

Step 1. Place the ruler adjacent to the object along its length.

Step 2. Adjust the object such that one end is along with the zero mark of the ruler.

Step 3. Look at the other end of
the object and read carefully the

mark aligned with this end of the
object. It gives us the length of the

object. Here, it is 10 cm. Thus, the length of the above pencil is 10 cm.

Fast Check

What is the length of the spoon?

______ cm

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