The Human Number Line

Today I’m sharing a fun activity that I like to do with my students at the beginning of the year in Algebra 2.  At the beginning of the year, I teach about subsets of real numbers.

First, get a stack of blank index cards.  I choose as many cards as I have students, so that everyone can participate.  Then, I write numbers in all forms on the cards.  Notice that some numbers that are the same, just written in a different form (ex. 1/4 and 0.25).  Also include radicals that aren’t reduced (with perfect squares as the radicand) and irrational numbers.  Really, you can do anything you want.  This should take you about 5 minutes.

Human Number Line
During class, give each student a card.  Then, direct them to put themselves into a number line.  I usually tell my students where zero is and which direction is positive and which direction is negative.  This helps the students get organized faster.

Once the students think they are in order, I start asking them questions.  I make sure I ask questions about repeating decimals.  I also ask about which number being bigger, pi or 3.14.

You could also only make half the amount of cards and have the students without cards direct and “coach” the students with the cards.

Sets of Real Numbers Sorting
Then, I have the students sort themselves into groups by their card.  First, I have them move into rational and irrational numbers.  Then, I’ll have them move into other sets (integers and non-integers, etc.).

If I have a class that seems very bright, I may try to stump them.  I’ll give them categories like real numbers and integers.  Students that are paying attention won’t know which category they fall into.

This is just a fun idea that helps liven up class at the beginning of the year.  It takes very little prep work, but gets the students talking.