More maths with Cuisenaire rods in Year 4

We've posted some of our work with Cuisenaire rods here already (see for instance our work on patterns in squares). Since then, we've used them in lots of other ways. Click on the headings to get more detail on the Year 4 blog.

Cuisenaire multiplication square

This was great fun to make, and the image of it has been a great resource to refer to:

Forgetting about square roots (not)

Not usually in the Year 4 (9 and 10 year old) curriculum, so we said forget about it, but of course this paradoxical injunction worked magic! Topped off with a little work on the differences of squares.

Algebra with Cuisenaire rod sums

This seems to be the ideal way to introduce the idea of using a letter instead of a number. (And thanks to Don Steward for the inspiration.)

Rozenn and Pythagoras

When Rozenn came in with something her dad had shown her - Pythagoras Theorem - the rods were the ideal way of quickly seeing that for the 3-4-5 triangle the theorem was right.

 Of course this is Secondary school work really, but just as in art we look at work by, say, Paul Klee, or in music we listen to adult musicians and composers, why shouldn't we look ahead and marvel a little in maths too?!

Tak-tiles

by Jessica

Tak-tiles are something that primary children can handle too (although most of the resources on the Web are secondary-oriented). With them algebra makes immediate sense, and they look good too.

We borrowed these ones from secondary,

Tak-tiles

but the shapes on the bottom right are a little tricky so we started with something simpler, a sort of puzzle on a special kind of grid:

First we named the basic areas (not shapes). No sooner had we named c than Sophie observed that a is made up of b and c. 

Harry put it as equation: 

b + c = a

So, armed with this, we were able to describe all the areas in our puzzle with abcs.
The blue rectangle on the right for instance is two of the a-squares, to be written 2a.

Someone noticed that sometimes you could describe an area in more than one way, for instance with the red shape on the left of the puzzle:

it's b + c, but it could be written more simply as just a.

So we got creating, filling the empty grid to make our designs:

The only rule was that everything had to be made up of abcs. There were to be no other-shaped bits that couldn't be broken up into as or bs or cs.
Here's some of our work:

The next thing to do was to start describing shapes in terms of area using abcs.
Millie's M for instance, we worked out to be 6a + 4b.

There's lots more. What would be the area of Max's green dragon be?
And then more tricky questions. Someone objected that those white "eye shapes" in Max's design aren't allowed. But when we thought carefully about it we realised we could describe it with the abcs.

You could easily have a go at creating a design yourself. Just click on the blank grid and download it. Then open it in Paint or whatever colouring-in program you prefer - and go.)

by Amandine