Are you ready?
Can you estimate lengths that use centimetres or metres?
Examples
Example 1
Choose the best estimate for the length of a classroom.
When estimating length, 1 \text{ cm} (centimetre) is about as big as your thumbnail, and 1 \text{ m} (metre) is about as long as two normal steps (for an average Year 3 student).
Estimate length
This video has a look at the units of millimetres \text{(mm)}, centimetres \text{(cm)}, metres \text{(m)}, and kilometres \text{(km)} and how to tell which are bigger or smaller.
Examples
Example 2
A bee is 11 \text{ mm} long. A fly is 14 \text{ mm} long. Which insect is longer?
When estimating length, we can use \text{mm} (millimetres) for very small objects,\text{ cm} (centimetres) for small objects, \text{m} (metres) for big objects, and \text{km} (kilometres) for much bigger objects or longer distances.
Length problems
This video shows you how to use some strategies to tackle problems.
Examples
Example 3
Choose the best estimate for the length of a fingernail.
To estimate the length of an object, we can compare it to an object where we have an idea already of its estimated length.
Choose the right unit
In this video we look at some familiar things, to get an idea of which unit of measurement we need to use.
Examples
Example 4
Choose the most appropriate unit of measure for the height of a tree.
1 \text{ mm} is about as thick as your fingernail.
1 \text{ cm} is about as wide as your fingernail.
1 \text{ m} is about the same as two steps.
1 \text{ km} is about the size of a one and a half laps around the school oval.