Fractions
If you already familiar with what a fraction is, how to reduce a fraction to its "simplest terms" and how to find the Lowest Common Denominator of two fractions, then skip to the next sections to learn how to add, subtract, multiply and divide fractions with 1 or 2 abaci. But if you aren’t so confident in your understanding of the basic terms and concepts, then , please spend some time in this section. Understanding the basics of fractions (the terms and concepts) is critical to understanding and performing calculations with fractions. Click on the link, Basic Fractions, to review the basic terms and concepts about fractions.
Add 3/20 to 16/60 = 25/60
Divide 20 into 60 giving 3. Multiply 3 times 03 giving 09. Add 09 (columns 10 and 9) in the numerator section (columns 6, 5, and 4). The new numerator is 25.
Many students use a Single Abacus to add, subtract, multiply and divide fractions. To do this, the final result of the calculation is separated into sections in the abacus. The numerator is in columns 6,5, and 4, the denominator is in columns 3,2,and 1, and the whole number for mixed fractions is in columns 9,8,and 7. The columns on the left side of the abacus are used in for the numbers needed to calculate the final result. Click on the link Single Abacus Fractions to learn, in detail, to add, subtract, multiply and divide fractions .
Add 3/20 to 16/60 = 25/60
Divide 20 into 60 giving 3. Multiply 3 times 03 giving 09. Add 09 in the numerator section of the top abacus. The new numerator is 25.
Using the Double Abacus approach, we separate the numerator (top number), to the top abacus, and the denominator (bottom number), to the bottom abacus. This repositioning of numbers in a fraction provides a much simpler process for adding, subtracting, multiplying and dividing fractions. Click on the link Double Abacus Fractions to learn this process and the steps to perform calculations with fractions.