Lesson · Grade 3 · Mathematics
Centimetres, metres and kilometres
- Grade 3
- Mathematics
- 1 min 23 s
- British Columbia
- BC3-MA-21
Three everyday benchmarks show how big each unit is: a fingertip is about 1 cm wide, a doorknob is about 1 m up from the floor, and 1 km is about a 15 minute walk. Then a unit is picked for a crayon, a door and a walk to the park, and each size is checked with its benchmark: about 9 cm (9 fingertips), about 2 m (2 doorknob heights) and about 2 km (two 15 minute walks).
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In one sentence
The question this lesson answers
Which unit fits a crayon, a door and a walk to the park?
We can choose centimetres, metres or kilometres.
Transcript
What the lesson says
Which unit fits a crayon, a door and a walk to the park?
We can choose centimetres, metres or kilometres.
One centimetre is about as wide as your fingertip.
One metre is about as high as a doorknob.
One kilometre is about a 15 minute walk.
Now let's pick a unit for each one.
A crayon is small, so centimetres are a good fit.
It is about 9 fingertips long, so about 9 centimetres.
A door is much bigger, so metres are a good fit.
It is about 2 doorknob heights tall, so about 2 metres.
The park is far away, so kilometres are a good fit.
The walk there takes about 30 minutes.
That is two 15 minute walks, so about 2 kilometres.
Use centimetres for small things, metres for bigger things and kilometres for far places.
Curriculum
Where this fits
- British Columbia, Grade 3
Mathematics, Geometry and measurement: measurement, using standard units (linear, mass, and capacity)BC3-MA-21
The outcomes and strands follow the British Columbia curriculum.
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