Multiplication and Division in Grade 1?

A couple of weeks ago I posted this picture:

Math - groups of

saying that it had something to do with math...

Well, the students had actually done all the colouring and lines and numbers on this page prior to me being in this class (which was either a grade 1 or 2 class... sorry... I really don't recall which right now!) so I'm not 100% sure on how their teacher told them to group the circles but I imagine she asked students to find similarities in the pictures (you can see that this student coloured #4 and 12 the same colours at least).

The day I was with them they were discussing what they had discovered.  

Someone said they noticed that 3, 9 and 15 both had circles in triangles

Another said that groups of 2's showed up in 2, 4, 6, and 10

Someone else noticed that groups of 4 (or circles in a square shape) showed up in 4, 8, 12, 16, and 20

Then the other teacher in the room asked them about numbers 1, 5, 7, 11, 13, 17, and 19

One student noticed that they were easy to spot because the circles all formed a larger circle. 

No one was really seeing that no other numbers go into those numbers (and I mean, honestly, why would they?  They are in grades 1 or 2 and haven't learned about multiplication or division)

So the teacher had 4 of them stand up and form a square like the picture for 4.

She asked them to then put themselves into groups of 2 which they could easily do and everyone had a partner.

Then she asked them to put themselves into groups of 3... someone was left out.

Next she had 6 of them stand up and asked them to make groups of 2 and 3... which we should know worked fine.  Then she asked for 4's and it didn't work.

Finally, she had 7 of them stand up and form a circle like the picture.  She asked for groups of 2 and someone was left out.  She asked for groups of 3 and someone was left out.  

And then we ran out of time.

But those students were thinking.

They were beginning to notice that 2 doesn't go into everything (or 3 or 4)

They were beginning to think of things in groups

They were wondering why they weren't able to form smaller groups out of 7

They were beginning to learn about multiplication and division in grade 1 (or 2)!

Wow.

I would be interested if anyone has ever come across this lesson anywhere because I would definitely love to see what else happens throughout it!