Multiplying with Single Digits
Double Abacus Approach
Short Course
This is a short course (slide show) on how to multiply with single digits. Just click on the arrow on the right to start the show.
Multiplying Single Digits
In the Multiplication Basics section, you learned that every multiplication problem involves 2 numbers: the multiplicand and the multiplier. The result of the multiplication is called the product. The first number will be the multiplicand and the second number will be the multiplier.
Important: When we multiply two numbers, the product will always be at least 2 digits. When the product of 2 single digits is a single digit, we will place a zero (0) in front of the answer. This means that 3 times 2 equals 06 (not the single digit). You will see why we need to do this as you study the examples.
Entering the Multiplicand
First, let’s enter the multiplicand (that is the first of the two numbers in your multiplication calculation). Starting in the left most column of the top abacus (column 13), enter the number from left to right. If the multiplicand is only 1 digit, enter it in column 13.
Entering the Multiplier
Next, we will enter the multiplier (the second number in your multiplication calculation). We will enter this number on the right side of the top abacus allowing 1 column for each digit. So, if the multiplier has 3 digits, enter the number in columns 3, 2 and 1. Now you are ready to calculate the product.
Calculating the Product
The product is entered in the bottom abacus. The starting column for the product is determined by adding the number of digits in the multiplicand with the number of digits in the multiplier. If the multiplicand has 3 digits and the multiplier has 2 digits, the product start in column 5 in the bottom abacus. Remember, when the two digits are multiplied, such as 2 times 2, the result is 04. Always add both digits.
Calculate the product by multiplying each digit of the multiplier times each digit of the multiplicand. Start the process with the right most digit of the multiplier and multiply it by each digit in the multiplicand. Add the 2-digit product of each multiplication to partial product moving from left to right.
All the rounds of the multiplication are complete when you have multiplied all the digits of the multiplier by all the digits in the multiplicand.
In our examples in this chapter, both the multiplicand and multiplier are single digits. Even though you already know the result of the calculation, these examples will show you how to correctly setup the calculation and arrive at the correct product. The asterisk (*) is used instead writing the work times in each multiplication example. For example, 4 times 3 is written as 4 * 3.
Examples
Now, let’s look at some more examples of this process. In these examples, the multiplicand will have many digits, but the multiplier will always be a single digit. Click on the link to show the steps to calculate the answer.
Example: 4 times 3
Example: 6 times 5
Example: 6 times 9
Example: 8 times 7