# Number Rods

Alignments to Content Standards: K.CC.B

#### Materials

• Unifix cubes or snap cubes, composed into rods with 1-10 cubes (or any counting sequence the class is currently working on within 20)

If the chosen number range includes numbers greater then 10, then make the rods using two colors so that the set of 10 in easily identified (see the image in the solution).

• A number line for the chosen number range

#### Action

The students count the number of unifix cubes then match the rod up to the correct number of the number line. Students can work in pairs or on their own.

## IM Commentary

This activity gives students practice counting for meaning. This task also allows students to see the size of the rod grow as the number gets larger.

One variation of this game is to give students a tub of unifix cubes and have them build the rods. However, this version is for students who are proficient counters. Students whose counting skill are still emerging will do better with the number rods already made for them.

As an extension, students can be asked to figure out why 2 colors were used to represent the numbers larger than 10. Also students can be asked what they notice about the cubes as you go from one number to the next (up or down). This could lead to a good discussion on one more and one less.

Materials Note: Very long rods of unifix cubes can break easily. Check to make sure each rod is intact before students start the game. Also instruct students to handle the rods carefully if the rods are longer than ten cubes. If the teacher does not have access to unifix cubes or snap cubes, or colored number strips could be made on heavy-duty paper.

To see an annotated version of this and other Illustrative Mathematics tasks as well as other Common Core aligned resources, visit Achieve the Core.

## Solution

Students will match the rods to the number line so that each rod is above its number.