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Our
STORY
About
THE LINEAR ABACUS
®
Key Characteristics of the Linear Abacus®
The Linear Abacus® is a foundational model of number for young children. It is made up of multi-coloured cubic centimetre beads which are threaded with a double string to keep the beads in place. Excess string is provided to allow children to perform various calculations with ease.
Bead Bank
The abacus string reflects the structure of the base 10 place value system. Each consecutive group of ten beads alternate colours, for example, ten yellow beads, ten blue beads and so forth. This pattern repeats 5 times over as there are a total of 100 beads on the string.
The Linear Abacus® is multifunctional and since cubic centimetre beads are used, the full 100-bead abacus string is equivalent to the measure of 1 metre. This means that the abacus string can also be used in measurement to model length, area (as a process of covering), and volume (as a process of filling).
Class sets can be used for rich collaborative problem solving and modelling to build deep number and measure intuitions. For instance, children can build a square metre, explore the number of strings used to circle an oval, or determine ways to convert between metric units of length, area, and volume.
The Linear Abacus® can be used across different mathematical areas such as number, algebra, measurement, and statistics.
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The different readings on the Linear Abacus®
The abacus string can be read in different ways. Each of these interpretations are based on the idea that each bead is 1cm in length (as the beads are a cubic centimetre).
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An individual bead on the abacus string can be thought of as a count because each bead is an object in an order. The counts are represented as numerals on the bead face and are colour coded red. The figure below shows a count of 5 discrete things. The numeral 5 links to the fifth thing counted.
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A span or a measure (in the sense of a ruler) on the Linear Abacus® starts from the beginning of the abacus string to the end or boundary of one bead to the next. These numerals are colour coded purple. On the abacus string this is shown as an annotated arrow below the string. The figure below shows an informal measure of 5 units.
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When two beads touch a point is found on the abacus string. Each of the points between the beads on the abacus string can be thought of as marks on a scale or a number line. These numerals are colour coded black and are marked as dots between the beads. The figure below shows the 5th centimetre mark on a scale.
Ways to use the Linear Abacus®
In the classroom the process of expressing and developing an understanding of concepts is facilitated by the discourse between teachers and students, students with other students, and students with themselves. For instance, if a child is given a simple number sentence (SNS) such as 18÷12=1½ and they are able to build a model on the Linear Abacus®, interpret a word problem, or do a calculation, whilst connecting all three interpretations simultaneously, then it is safe to assume that they have understood a concept in arithmetic.
In this problem students are comparing 18 to 12 multiplicatively.
SNS
In the World
Jack has 18 marbles in a bag, and Jill has 12 marbles in a bag. How many times more marbles does Jack have than Jill?
Linear Abacus® Model
Start by locating Jack and Jill’s bead on the abacus string as both are things that can be counted.
Then ask yourself, “how many times does Jill’s total go into Jack’s total?” The arrows above the beads show the answer and dashed beads have been included in the diagram to show how many times Jill’s total goes into Jack’s total. This can also be performed with a second abacus string.
This concrete representation shows, one lot of “what Jill has” and another half of “what Jill has”.
Another way to interpret this is to let 12 marbles be one full bag. If 12 represents 1 bag, then 18 is one bag and 6 out of a second bag.
Using a Calculation
The diagrams below include both the additive and multiplicative interpretations.
An additive interpretation
A multiplicative interpretation
This answers the word problem i.e., Jack has 1½ times as many marbles as Jill. 1½ is a multiplicative relation as it focuses on ‘how many times’ not how many.
For more ideas on how to use the Linear Abacus® when teaching numeration and arithmetic, you can purchase the Concise Instructional Manual for the Linear Abacus® which provides descriptions and detailed examples with annotations.
The manual could be used by a parent to support a child, for home schooling, by a teacher looking to innovate new approaches, or as a systematic review of key concepts.
Volume is explored through ‘filling’ boxes. The Linear Abacus™ helps students understand the formula to find the volume of prisms i.e., base area x height.
Area is explored through ‘covering’. Here a square metre is being constructed. Students discovered that 100 strings were required to cover the square metre. The Linear Abacus™ helped them see the submultiples of the unit and convert between units.
Numeration- naming numbers using base 10 place value. The Linear Abacus™ helps students expand numbers multiplicatively.
1 2 3
Counting using one-to-one correspondence to order an unordered collection. This is the first notion of a number.
The basis of counting and additive thinking.
The basis of measuring and the foundation of multiplicative thinking.
1 2 3 4 5
5 beads long
The beginning understanding of scale and algebraic thinking with numbers.
5cm
12 18
Jill has Jack has Bead Bank
The Linear Abacus® is a new classroom tool used to help students learn and make meaning of mathematical concepts. It was designed to provide a consistent multiyear resource for teaching algebraic thinking as the basis for STEM subjects. The development and inspiration of the Linear Abacus® was motivated by the need to find simple but rich manipulatives that can be used easily in the developing world to teach number, measure, and arithmetic from prep through to grade 8.
For children, learning to manipulate materials to make meaning of mathematical concepts and to generate mathematical activity is a crucial step in their development. Meaning can be achieved as they learn to use and talk about the materials to build intuitive understanding of key mathematical ideas. The Linear Abacus® allows children to learn through their actions and gestures, through their observations, by constructing models, by translating mathematical ideas, or by demonstrating how numbers interact with their world.
For teachers, this tool provides a wholistic approach to the teaching of numeration and arithmetic, where language and number interact in framing concepts. The Linear Abacus® embodies all the arithmetical relationships covered in the primary and early secondary stages of schooling and can be used to teach arithmetic for understanding. This means that the teaching of arithmetic with the Linear Abacus® goes beyond rote learning procedures. Teachers can help students generate meaning by coordinating various communications in the classroom and three important types of activities:
1. modelling with materials,
2. solving word problems, and
3. performing calculations.
Testimonial
" I wish to say how terrific the linear abacus resource worked for a particular student in my class today.
The student I am mentioning is a student with a learning disability. The students were engaging in a task that required them to work out the area and volume of a particular shape. It was heartening to see a student who regularly struggles with this type of maths to be able to 'click' with an activity because he was able to manipulate the abacus string/s to assist his understanding. He was independent throughout and experienced success. My class of 6s have used the linear abacus in many different applications during this year and I've found it particularly helpful in consolidating understanding number tasks "
Jennifer Fenech, Teacher St John the Apostle Primary School
Linear Abacus®
0472 800 764
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