To assess prior knowledge, gather students together. Give them 20 connecting cubes, 10 of two different colors in a resealable plastic bag. Ask students to organize their cubes into one train of 10 and 10 cubes that are separated, as shown below.
Display a Numeral Card and ask each student to show you the number using his or her cubes.
Look for students who understand that 10 is a unit that can be counted without separating the cubes that compose it. Make note of students who have an emerging understanding of place value and those who do not.
To begin the lesson, show the numeral card for 11. Ask the students to name the numeral and tell them that they will model this numeral in several ways.
Ask the students how many groups of ten and how many ones there are in 11. Students will be able to "hear" the number of tens and ones more clearly in the higher decades such as the 40s. For example, 46 means 4 tens and 6, with the "ty" standing for "tens and." This is less evident in the teens, and even subtler in the numbers in this lesson.
Call on a volunteer to count out ten cubes of one color (blue is used in the model) in a tower. Then ask him or her to add one cube in another color onto the tower. Ask the student to count aloud to determine the number of cubes.
Invite the rest of the class to make their own towers of 11, using 10 cubes of one color and one cube of another color. Show the numeral card for 12 and ask the student to make a tower with 12 cubes in the same way.
Have the class make a 12tower. Then hold up one tower and ask how many connecting cubes were used to make it. (11 or 12)
Call on a volunteer to hold up his or her other tower, and to say how many cubes were used to make it. Then compare the two towers. Have students display their tower, compare their towers with a partner, and name the number of cubes used to make each tower.
After they have compared the towers, ask students to trace one of the towers and color it to match the cubes they used. Display the numeral 11 or 12. Tell students to make a large 11 or 12 in the air, then write the appropriate number under a tracing of the tower with that many cubes.
Next, distribute the Ten Frames activity sheet.

Ten Frames Activity Sheet

Ask students to place 11 connecting cubes in it with one per section. Ask them to count aloud as they do so.
Be sure that they fill the blue frame first. This will help them visualize 11 as "ten and one more."
Repeat making a tenframe model for 12. Ask students to suggest ways the representations for 11 and 12 are different.
Now ask students to take one bean stick and show how the number 11 might be modeled using a bean stick and a loose bean. Repeat making a model for 12.
