Each rod increases in length by the length of the smallest rod, or 10 centimeters.
The longest rod is 10 times longer than the smallest rod.
- Invite the child to the lesson. Unroll a rug. Show where the work is on the shelf and name the lesson.
- Starting with the shortest rod, carry the rods one at a time to the rug. Place them on the rug in mixed-up order with all of the edges lined up on the left.
- Move the longest rod and then the shortest rod to the bottom of the rug. Point to the longest one and say, "This one is long." Point the the short one and say, "This one is short." Then mix the rods back in with the rest.
- Select the longest rod and place it at the top edge of the rug. Find the next longest rod and place it just below the longest rod touching it.
- Continue until all of the rods are in order.
- Clean up: Starting with the longest rod, carry the rods one at a time back to the shelf. Roll up and put away the rug.