Multiplying Decimals

I was thinking about multiplication. Arrays are often used in primary schools. They are a great model for small whole numbers. What happens when we want to extend this though into larger numbers or decimals? And how does 1/3 of 1/2 fit in?

So I had a play with geogebra to see whether I could bridge the gap... Here are my initial thoughts.

I have created a series of interactives that show area as an overlap between inequalities. The first one simply shows the area of a rectangle with the lengths of each side as sliders. I think it would seem familiar enough, though the links between arrays and area should probably be made explicit.

Then I created a series of similar interactives that show larger numbers and decimals less than 1 and finally decimals between 0 and 10.

I am not sure if this is too contrived but it does bridge a gap into decimals.

The full worksheet with guidance can be found here: https://www.geogebra.org/m/mgxFSGDQ

I think that the different size of squares in each interactive is difficult to reconcile. I think I would realistically want a zooming option, and the option to pick whole numbers, decimals to 1dp or decimals to 2dp on the same interactive, then it might feel like an extension of the same exploration. 




Any thoughts and feedback welcome!


Comments