Read an Excerpt
THE MAGIC OF
MULTIPLICATION
What is multiplication? How do you write a multiplication problem? How do you read one? What are you actually doing when you multiply one number by another? Once you can answer these questions, you are well on your way to discovering the magic of multiplication. There are four basic operations in mathematics: addition, subtraction, multiplication, and division. Each of the four basic operations can be expressed as a symbol. The plus sign (+) tells you to add two numbers together. The minus sign (-) tells you to subtract one number from another. The multiplication sign (×) tells you to multiply one number by another. The division sign (÷) tells you to divide one number by another.
The problems 7 + 3, 7-3, 7 × 3, and 7 ÷ 3 are different problems that have different answers.
When you use the multiplication sign (×), you can write the problem either horizontally or vertically. One hundred fifty-two times nine can be written as either 152 × 9 or as:
There are other ways to indicate multiplication besides using the multiplication sign. Sometimes a multiplication problem is written by putting a dot between the two numbers like this: 5 • 12, which is the same as 5 × 12, or five times twelve. You could write four times six hundred twenty-two as 4 × 622 or 4 • 622. Another way to indicate multiplication is by putting parentheses around the second number. For the problem, three hundred sixty-four times seventeen, write 364(17), 364 × 17, or 364 • 17.
You can write the same multiplication problem five different ways.
- Forty-eight times two
- 48 × 2
-
- 48 • 2
- 48(2)
Now that you know how to write multiplication problems, it's time to find out the names of the three parts of a multiplication problem. Look at the problem 17 × 5. Read this problem as seventeen times five. The number 17 is called a "factor" and the number 5 is also a factor. The answer to the problem (in this case, 85) is called the "product."
What are the parts of 9 • 6 = 54?
- 9 is a factor
- 6 is also a factor
- 54 is the product
Try a different format. What are the parts of 10 • 2 = 20?
- 10 is a factor
- 2 is a factor
- 20 is the product
Identify the parts of this problem: 6( 111).
- 6 is a factor
- 111 is a factor
- The product is not given.
Multiplication is an essential mathematical skill. You will use multiplication every day of your life, so start practicing and soon you'll become a multiplication master. Then you can proudly display the multiplication master certificate at the back of this book.
