Thursday, 10 December 2015

Measuring Decimal Lengths

To help us enquire further into our central idea:

.......we have taken a segway into measuring length to help us understand how we use decimals in real life situations.  In word problems related to length that the children pose for others to solve, we have been finding out how to convert, add, subtract, multiply and divide decimals. Learning how to manipulate decimals with practical examples helps children to understand not only the skill process, but more importantly the why behind the skill.

To practise converting decimal lengths, the children were given lengths of different snake species in the world.  They converted the average length of the snake species and the longest length recorded. We were really amazed at these lengths and wondered how we might react if we came across one in the wild.

After this, we were given a choice of activities to investigate:


Choose one of the snakes.

Find the average length of the baby.

Make the average length of the baby using a paper strip.  Record the length in metres, centimetres and millimetres.

Make the average length of the adult using a paper strip.  Record the length in metres, centimetres and millimetres.

(This activity was aimed to help some of the children still new to the idea of converting decimal lengths from metres to centimetres etc.  It was also hoped that it would help them to visualise what 4 metres etc actually looks like)


We were amazed at the size of an average baby anaconda, an average adult and the longest length recorded!  The children creating this needed to convert the lengths from decimal metres to centimetres (and millimetres as an extension option) and then showed us how they calculated the difference between the decimal lengths.


( Comparing the sizes of an average baby and adult of king cobra and a python)

More Challenging:

Choose one of the snakes.

Think of 10 snake lengths that could show how it got the average length.

Make the snake lengths using paper strips. Record the length in metres, centimetres and millimetres.

(It was hoped that this would make an interesting review on averages that we have been learning about this year and help some children gain a deeper understanding of what an average actually is)

Even More Challenging:

Create a visual graph that shows the distances and compass directions some of us migrated from before arriving in Lausanne.

You need a map ratio key so others can understand.  

You also need a compass rose (directions).

( To do this activity, the children needed to create map ratio scales, use an atlas to find the directions of the cities we come from Lausanne where we live and thought a lot about using millimetres to help create strips of paper that would accurately represent the distance)

The majority of children were keen to do the last activity and some chose the first.


Distances and directions some of us come from with a ratio map scale. I thought this was a really creative way to present her maths findings.

These children decided to show the distances as a column graph.  I think maths thinking is so much better when we give children the opportunity to choose how to tackle an activity rather than constantly being told exactly what to do.  I wouldn't have thought of a column graph, but these children did and it made perfect sense to record the findings this way. 

I really loved the thought that went into this ratio map scale of distances and compass directions we come from:

A close upè of the centre:

Look how far away Melbourne is compared to other cities we come from!

When sharing our maths thinking, we asked questions of strategies they used, how did they know they were accurately showing the lengths and what they were proud of achieving.

In our whole class reflection, children brought up how this helped them to understand further that maths thinking IS creative thinking and they also mentioned how they appreciate being given options of what sort of activities to investigate and to investigate in ways they think is best.  Sounds like what real mathematicians do do to me!

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