To open this lesson, choose a counting book, such as one of those listed in the Bibliography of Children's Counting Books. One Gorilla or the M&M’s Counting Book present the same content in very different ways. As children listen to the story, have them model each number they hear by adding one connecting cube to a train of cubes and writing the numeral and number word for each model.
(Note that if you would like a more permanent record of their present level of understanding, have them color graph-paper squares to show the number. If you choose not to read a counting book, you might sing a familiar counting song, such as “1, 2, 3, 4, 5, I caught a fish alive.”)
Next, give each child ten to twelve connecting cubes. Hold up a number, such as 8, and ask the children to make a train with that many cubes, lay it flat on the desk, and record the number of cubes. Then ask students to make a second train with one less cube and then put the trains together to compare their lengths. Ask them to record the comparison they have just modeled using the equation, or horizontal, format—for example, 8 – 7 = 1. Now have students record the comparison using the vertical format.
Next, chose a “counting back” book, such as Ten Sly Piranhas, Ten Monsters in the Bed, or Five Little Monkeys Jumping on the Bed. Have children take one connecting cube at a time away from a cube train as the story is read and record each subtraction in equation form. Then have them stack ten cubes vertically in a tower. Ask the students to remove one cube at a time as you count backwards from ten or reread the story. Ask them to record each subtraction in the vertical format.
When the students are ready, name a number and ask then to tell or show with cubes what number is “one more” and which is “one less.” You may wish to record their responses on the One More, One Less Activity Sheet. Ask the children to draw trains that show one more and one less. Then ask them to repeat the activity with towers. You may wish to ask them to save these as entries for their portfolio.
