Begin by reviewing the number zero, and how integers are less than zero. Have students give examples of a situation that can be described with a positive or negative value (ex. giving away money, swimming up through the water, driving back to get something you forgot).
Give each student four index cards. They should listen carefully and place a different value on each card:
- A positive whole number between 1 and 10
- A negative whole number between -1 and -10
- A positive decimal number between 1 and 10
- A negative decimal number between -1 and -10
After the students have written their four numbers, have them put them in order from smallest to largest on their desks. Check for accuracy.
Next, have the students combine cards with a partner and put them in order from largest to smallest. Check for accuracy.
Next, students in each group should combine and order cards (16-20 numbers). This one can be a competition, whoever finishes first gets bragging rights.
Finally, have all of the kids put the cards back in random order facing down in the middle of the group. Each student should pick one card without looking at it or showing other students.
When the teacher says go, the object of the last activity is to order the students in the class from smallest to largest. Each student places their integer card on their forehead, and they can’t look at it. The students have to stay silent the entire time. They must arrange each other in order without knowing what their own number is.
After everyone has been arranged, check for accuracy.
Choose a few students at random to leave the line and pick a new number card from the desks. They now have to figure out how to place themselves back in the line. Continue until all students have been moved around.
In order to leave the line and go sit at their seat, students have to come up with a situation that describes their integer card.
In closing, ask questions such as:
- How is 3 greater than -25, even though 25 is a bigger number? The negative sign tells you that you are moving backward away from zero. -25 is like owing 25 before I can even get back to zero. Three is positive.
- Why do we need negative numbers? So we can describe situations less than zero.
- Is a negative decimal number still a negative number? Yes, whole numbers, decimals, and fractions can all be negative.