My dd just started Singapore 1A last week and today I felt that we should have an extra lesson concerning equality/inequalities of sets. I noticed that during Essential Math and 1A that she wasn’t always answering these types of questions correctly. So, I got out her bucket of animal figures, our trusty Cuisenaire rods (just two of each color), and I made up some cards with the symbols = and < (this last card can easily be flipped around to make >).
My dd lined up the rods in “stair formation” and then I made two sets of equal numbered animals. I had her first identify which rod stood for the number of animals in each set and then she had to place a card showing the relationship between the sets (in this case =). We continued to do this for all different combinations and then she made up some problems with me. At the end, I had her tell me the relationship between the two numbers as well (eg. “5 is greater than 4” or “4 is less than 5”).
I think that I will expand on this activity next week by adding in a third set.