This lesson can be used as a pre-lesson for the Give Me 10!lesson plan.
Students will be able to add three whole numbers whose sums are within 20.
Students will be able to explain the steps to add three whole numbers using manipulatives and peer support.
Display a bag, and tell students that there are ten cubes in the bag.
Show students three different color cubes: red, blue and yellow. Label each color cube.
Ask students, "How many of each color could there be in the bag?"
Display the sentence frame, "There could be ________ ________ cubes, __________ _________ cubes, and ________ ________ cubes." Remind students that in English the adjective comes before the noun that it describes (e.g. the red cube, not the cube red).
Model a possible solution, "There could be four red cubes, three blue cubes, and three yellow cubes." Draw the cube combination on the board. Remind students that "could" means that there may or may not be that many.
Model other possible combinations. Ask guiding questions such as, "If there are three red cubes and three blue cubes, how many yellow cubes would there be?" Think aloud, adding three and three, and then subtracting six from the total number of cubes, ten.
Dump the cubes from the bag so that students can see them, and write an equation that shows the number of cubes of each color on the board.