Which numbers are real? Rational? Natural? Whole? Here is an easy activity to help meet the number sets objective.
I made this set of cards with numbers from the above sets. As students enter, I’ll give them a card. Then I will ask the students to walk around the room, see what numbers others have, and organise themselves into groups based on their number. The instruction is purposely vague enough that many possible groupings are possible. When students have grouped themselves, I’ll start a group discussion about the way they are grouped.
I anticipate (I haven’t tried this activity yet) that I may have to prompt the students to think again about the groupings and ask questions to help them explore the idea of number sets. And then maybe ask if there are some numbers that are “purer” than others. I think students have a sense that whole numbers are more “number-y” than items like 2.4 or negative four fifths.
I think it would be interesting to put students holding whole number cards in the centre of the room and then build the number sets outwards around them. I think this would elucidate the idea of natural numbers being contained in the set of integers, and rational numbers being contained in the set of real numbers.
I think it’s my responsibility to introduce the names for the number sets once students have developed the concepts behind them. I’ll write the names and symbols for them on the board to conclude our discussion.
How do you teach about number sets?