3-D shapes and nets, oh my!

Two weeks ago I was able to convince my man that we should team teach a maths lesson together. 
Some background info ...
Years ago, when we both decided we wanted to be teachers, I remember saying that it would be funny if we worked in the same school together. I think his words were something along the lines of "I would hate that" (okay, probably paraphrasing slightly and putting words in his mouth, but you get the gist.)
Fast forward to a year and a half later when I was moving back to England, after qualifying in California as a teacher, and could not get a job. An opening came up at his school and I was offered the job. Three and a bit years later and we having been working together, albeit in different years, and it hasn't been too bad.

The lesson ... 
In our school, year groups are set based on ability for maths and English. Dan and I are both Set 1 teachers, meaning we have the highest ability students for maths. I thought that this year, being in Year 3, it would be good to have some students from Year 5 help them with newer concepts. Our set has been working on shape, but hadn't gone massively in-depth with it. Dan had mentioned wanting to make 2-D nets of 3-D shapes with his set, when I suggested we join our lessons. After some humming and harring, Dan thought 'why not?'. 
Our lesson consisted on having all 50 students working in the hall. We paired off the year 3 and year 5 students and asked them to discuss everything they knew about 3-D shape. We also posed the question of 'What does 3-D mean?'. This was great as my students knew the very basics of what made up a 3-D shape and the year 5's were able to extend my students' knowledge. This exercise was also able to reinforce 3-D shape concepts to the older students.
The next task was for students to chose a 3-D shape and try and make a 2-D net. 

Students working together in their pairs or threes. They were able to chose any shape and tried to trace around and create their nets.

Some of the amazing nets the students were able to create.

The year 5's had made nets the previous year when they were with me in year 4, but the year 3's were only learning about the different 2-D shapes that make up 3-D shapes. This lesson was awesome in reinforcing the different faces that create a 3-D shape and really explaining the other properties. The students were able to understand about the edges of a 3-D shape because this was where their nets would be stuck together. 

An example of a cuboid net being folded into its 3-D form.

Now I know this lesson was probably 10x more helpful for my younger ones, but we were able to extend the older students. Once the students created their nets, their next challenge was to create another net of the same 3-D shape. Most the year 5s were convinced that it couldn't be done. After jigging their shapes about some pairs were able to prove themselves and other doubters wrong. 

The aftermath ...

My students loved this lesson. We had about 10 minutes at the end, in just our set, to discuss what we enjoyed about the lesson and the new ideas they learned. I was so impressed to hear them explain that 3-D means three-dimensional, which was length, width and depth. They were more secure in their understanding of shape vocabulary. I also loved that some students said they liked meeting new people in the school!

Have you ever had the chance to work with other classes or year groups on projects? How did you manage it?

Cheers!

Becky