Teacher Note: As you prepare to teach this unit, you may wish to consider what management strategy you will use to distribute the fish-shaped crackers. Packaging the
fish-shaped crackers in resealable plastic bags, one for each student, will keep the material sanitary.
To open this lesson, provide each student with crackers, two paper plates, crayons, and graph paper. Then read a counting book about fish (one option is Fish Eyes: A Book You Can Count On by Lois Ehlert) or some other counting book.
As the students listen to the story, have them model each number named by adding one fish-shaped cracker to a plate, writing that numeral at the beginning of a row on the graph paper, and then placing one fish cracker per square to show the number. [Encourage students to have rows of 10.] Then ask them to remove the fish, one row at a time; coloring the squares in that row that had held fish crackers. Have students color each row a different color using yellow, purple, and other colors of their choosing. If you choose not to read a counting book, you might sing a favorite counting-up song, such as "This Old Man," and have the students model and record the number featured in each verse.
To the tune of an easily-remembered song, such as "A Hundred Bottles of Beer on the Wall," sing a more appropriate counting back song, "Ten Little Fish on the Plate." Have the students place crackers on the appropriate bar on the graph they created in the activity above as they sing each verse of “Ten Little Fish.” [This activity allows you to determine whether any students have trouble matching numerals to sets, counting, or writing numerals.] Now ask: How many more squares are colored
in the yellow bar than in the purple bar? How do you know? [Possible answer: 1; I counted one more. This question introduces the new mode of subtraction, the comparative mode.]
Next hold up a number, such as eight, and ask the students to put that many fish-shaped crackers on a plate and record the number of crackers. Then ask them to make a second plate with one less cracker.
Now tell them they will compare the number of crackers on each plate. To do this, have them remove pairs of crackers from the plates by taking one cracker in each hand from each of the plates and placing the crackers in the bag until crackers are left on only one plate. Then have them count the crackers left on the plate. Ask for a volunteer to model and record the comparison using the number sentence [equation or horizontal] format. [For example, 8 – 7 = 1.] Now ask for a volunteer to record the comparison using the vertical format. Encourage the students to describe the comparison in two ways, in one instance
using the word "more" and in the other instance using the word "less." [For example, there is one more cracker on the plate that had eight crackers. There is one less cracker on the plate with seven crackers.]
For the next part of the lesson, students will need access to the Adjustable Spinner.
Ask a student to name a number from 5 to 10. Divide the spinner into that many parts. Now call on a volunteer to spin the spinner and tell which number came up. Ask the students to show the number with fish-shaped crackers. Then tell them to show a group of crackers that is one more than that number, and then a group that is one less. You may wish to have them record their responses on the One Less/One More Activity Sheet.
Repeat with other volunteers.
To end the lesson, have the students divide some crackers between two plates, then remove a cracker from each plate until all the crackers on one plate are gone. [If you wish, you may encourage them to eat each pair of crackers as they remove it. If you prefer to use the crackers another day, be sure each bag is labeled with the student's name and closed securely.]
