Thursday, 17 May 2018

Estimating Volume Morning Prompt

Providing children with invitations in the morning when the first enter the classroom can be an engaging way to appreciate mathematical thinking in different contexts.

As we are currently exploring measuring volume and capacity, I found a small jar of sweets and when the children entered, they could choose to try to estimate how many sweets were in the jar.

On their sticky note, they were asked to explain the strategy they used to estimate.

Later in the day when we visited the maths prompt, children were able to verbally share the startegies they used. Some very interesting strategies and connections were explored.

Some examples of estimating strategies:




As the sticky notes were scatttered all over the board, a classmate suggested we arrange the numbers in order to make it easier to see how estimates. We agreed this was a good idea and so some of us arranged them in teens, twenties, and thirties/forties.

What is the range of estimates?

- We determined the range was 30.


- Because the smallest estimate was 12 and the largest was 42.

So, what does the range tell us?

- The difference between the highest and lowest.

- How big of a difference people estimated.

Can we explain what the range is in other ways?

- The range can tell us the middle amounts.

It was then time for the exciting part- counting the sweets to see who would win.

We counted 19 sweets.

No one had estimated exactly 19 sweets, so, who wins?

- Whoever was the closest.

We had two students estimate 20 so they won the sweets.

We wanted to hear again what strategy they used, so those learners shared again the strategy they used when estimating.

When counting the sweets, some wonderings emerged which we have added to our wonder wall:

- Do the companies count out the sweets per jar?

- How do they know how many sweets to put in the jar?

- The jar says it is 45 grams, so do they measure the mass of the sweets?

- Do they just estimate the number of sweets?

- Would all the jars have exactly 19 sweets?

And some theories were discussed:

- The jar was packed full, so maybe they are thinking of the volume of sweets- the maximum amount that fits in.

- Since it says 45 grams, I think they must weigh the sweets but they round them up or down so if the sweets weighed 48 grams they would say that is close enough.

Obviously, the opportunity to win some sweets enticed the children a lot. 

Having regular maths prompts / invitations as part of a morning routine can (even without winning sweets) help engage children in creating or testing mathematical strategies in relaxed and real life context ways.

They can also serve as an interesting informal assessment when spending time listening to or reading strategies each child is trialling to use. Often, they come up with really creative ideas that can be tapped into for further investigations.

1 comment:

  1. I especially like the suggestion (to organise the estimates) and questions. When you get smaller packets, like Smarties, there seem not to be the same number, and definitely not the same colours in each box. It makes you wonder what the packing process is, and whether we can tell anything about it from the numbers.


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