La Texican, we use Singapore math and skip from chapter to chapter depending on interest. We may not have touched n the arithmetic in a book, but have completed all the geometry and measuring in that book and the next one as well. They also have great activity ideas in the home educator guides.
I'm going to argue with your husband. Both containers and the fluid in them are at room temperature, and we're measuring volume only. He didn't read the question right.
Maybe I should ask him which group has more pieces. That's the thing. The early Singapore math is big on sets.
That's a different question. (and an earlier developmental stage according to Piaget)
The way I worded the question (using 2x2 duplo blocks) was "see, this block covers one square of the paper."
I then laid out four blocks tight together. "this is one way to arrange them"
move the blocks apart "this is another way. Which arrangement covers more of the paper?"
ETA: oh man, I just reread your post, sorry, I was thinking you were talking about conservation of area, not conservation of number. I also didn't realize he was three. I think he's not ready for math yet.
