The Number Rods
Materials:
10 wooden rods whose dimensions are the same as the red rods. The shortest rod is painted red and represents “1”. The following rod is painted half red (10cm) and half blue, and represents “2”. The remaining rods, 3 to 10, are painted in alternate sections of red and blue.
A large rug (or two small rugs)
Purposes:
To experience the name, quantity, and the sequence of the numbers 1 – 10
To introduce the concept of number as represented by a single entity
Counting using 1-to-1 correspondence
To provide a foundation for the base-ten system of mathematics
Age: 3 ½ – 4 ½
Preparation: The child is able to build the Red Rods in sequence.
Presentation:
Invite the child for the lesson on the Number Rods, to get a rug, and to unroll it horizontally.
Show the child how to carry the rods vertically, with both hands, in the same manner as the red rods. Beginning with the shortest rod, together place the rods on the lower half of the rug, placing them at random.
Visually scan the rods. All should be oriented with the red segment on the left. Turn any over that are not oriented in this way.
Tell the child you are looking for a specific rod.
Locate the longest, the rod of ten, and place it at the top of the rug, aligned at the rug’s left edge by holding it at either end with the hands.
Locate the next longest, the rod of nine. Using the same hand placement, place the rod below the rod of ten descending downward, aligned at the left edge of the rug.
Invite the child to continue building the stair.
Once the child is complete, pull down the first three rods.
Isolate the rod of one in front of the child.
Place the hand flat on the rod and count aloud (one). Place one hand at either end of the rod indicating the whole and say the number of the rod again (one).
Invite the child to count the rod in the same manner.
Isolate the rod of two in front of the child.
Place the hand flat on the rod and count aloud each segment when it is touched (one, two). Then place one hand at either end of the rod indicating the whole and say the number of the rod again (two).
Invite the child to count the rod in the same manner.
Repeat in this way for the rod representing three.
Invite the child to count the rod representing three.
Commence a Three-period Lesson. Include opportunities for the child to count in the second period commands. In the third period, ask the child to count the rod and tell you what it is.
If the child is interested, introduce three more rods.
When the Three-period Lesson for the second set of rods is complete, invite the child to mix up the rods and build the stair again.
Note: Over the next several days, continue this lesson until the child can count and identify each rod.
Control of Error: The segments on the rod serve as a guide.
Following Exercises
Bring Me Game: The rods are laid randomly on a rug across the room. Ask the child to bring a specific number rod. Have the child count the rod they brought to verify. Hold the rod for the child as they count and reinforce them counting left to right. If the child brings the wrong rod, have the child count what is there, and repeat the request you gave the first time.
Pedagogical Notes:
The child is the same age as the child who is working with the red rods. The child must have the foundation of the grading sensorial materials before this lesson.
“Their proportions have already been studied in the sense exercises. Here they are judged mathematically, and this provides an initiation to arithmetic” (Montessori, Discovery of the Child, 1972, p. 264).
Have the number rods placed on the shelf with the left end aligned at the edge of the shelf or along an indicator on the shelf. The red ends should always be on the left.
Always count from left to right.
If necessary, guide the child’s hand from one segment to the next.
Review previously presented rods before adding additional.