Page 116 - Math Smart - 7

CHAPTER 5.2

In this chapter
Suitable Units of
Pupils should be able to:
• choose suitable units
of measurement to
Measurement
estimate, measure,
calculate and solve
problems In everyday
To find a suitable unit of measurement of something, we should first estimate
contexts
how big it is. Imagine the size of the objects you are estimating or imagine
measuring them in relation to other objects.

Think and Shan

Should an elephant and a mouse be measured in grams or tonnes?
• The average mass of a mouse is 20 g. The mass of a mouse in tonnes
would be 0.00002 t (2 hundred thousandth tonnes).
• The average mass of an African elephant is 5 t.The mass of an African
elephant in grams would be: 5 000 000 g (5 million grams).
It does not make sense to measure the mass of a mouse in tonnes or an
elephant in grams. We need to select the unit of measurement carefully to
work with sensible numbers.

Check My
^ RECALL Understanding

O Write in the suitable units of measure.
O A barrel can hold
a) The length of a bank note is 12
more water than a
b) The thickness of a coin Is 3
bucket Would you
c) The height of a classroom wall Is 3000
use a barrel or a
bucket of water to d) The capacity of a mug is 250 .
wash your car? e) The mass of a car is 900 .
f) The mass of a pen is 30 .
O A football field is
much larger than a g) The capacity of a teaspoon is 0.005
garden. Which unit of
© Match each item to its correct unit of measure,
measurement would
you use to measure item Unit of measure
the football field?
Car length • litres
Mass of a cell phone • metres
Amount of water in a bathtub • milliliters
Length of a pencil tip • grams

Amount of water in a raindrop • millimetres

Measurement