 # The Soroban

##### Created by Kendra Hutton, Unber Khan, and Mitra Malekan #### Curriculum – Number Sense and Numeration

Read, represent, compare, and order whole numbers to 1 000 000, decimal numbers to thousandths, proper and improper fractions, and mixed numbers; solve problems involving the multiplication and division of whole numbers, and the addition and subtraction of decimal numbers to thousandths, using a variety of strategies; demonstrate an understanding of relationships involving percent, ratio, and unit rate.

#### Goal

To show students a visual representation of numbers with patterns of beads that is easy to remember.

#### Materials

• Large popsicle sticks
• Thin wooden sticks that will hold the beads
• Glue guns
• Dry-erase markers
• Overhead sheets to write on with a white sheet of paper slipped inside for better legibility*Optional: Due to the time constraint, we provided the students with pre-made Soroban skeletons. The skeleton can be made by taking 5 sticks and hot gluing them between two large popsicle sticks.

#### Lesson Introduction

• Ask students, “What do you think people used years ago to calculate large numbers before we had calculators?”
• Discuss possibilities and then show and let students explore the Soroban.
• The teacher then asked the students if they have ever seen or used this before?
• Share a brief history of the Soroban and relate its use to the base-ten blocks (see Appendix A).

#### Activity

• Introduce the different features.
• To ensure students learn and remember how to use the Soroban while staying engaged, present the following:
• The red beads are called the Heavenly Beads: worth 5 units each.
• The white beads are called the Earthly Beads: worth 1 unit each.
• The line in the middle is called the Beam.
• In order for a number to count, the bead(s) must be touching the beam. For example, the heavenly beads have to come down and touch the beam to count while the earthly beads have to come up and touch the beam to count. To show the number zero, the heavenly beads are up in heaven and the earthly beads are down on earth.

#### Activity

• Introduce them to the materials needed to make their very own Soroban.
• The teachers model and provide easy to follow, step by step instructions (see Appendix B).

#### Closure

• Ask students “Why do you think the 1s column (right) only goes up to 9?”
• Together in small groups, begin to represent numbers one by one to ensure that every student understands the basics.
• Begin by representing one digit numbers moving our way up to 5 digit numbers, as follows: 2, 7, 13, 69, 325, 6479, and 10000.

#### Possible Extensions

• Break students up into pairs and ask them to develop problems and then solve them.
• Use the Soroban to practice bigger numbers and more complex concepts.