Like addition and subtraction, multiplication also has number families. A number family is made up of two or three numbers. Look at the example below.
In this example, we have the three numbers 4, 5, and 20. Most multiplication number families have two lesser (smaller) numbers. When we multiply these numbers together, we find the greatest (larger) number. In this case, 4 and 5 are the lesser numbers. When we multiply them together, we find the greatest number, 20.
A multiplication family has one or two multiplication facts. Let's figure out the first multiplication fact for this family. What is the multiplication fact that begins with the first lesser number?
4 x 5 = 20
The second multiplication fact for this family is:
5 x 4 = 20
Let's look at another example.
In this number family, our lesser numbers are 9 and 10. When we multiply these two factors (numbers multiplied together), the product, or answer, equals 90.
What are the two multiplication facts for this number family? Remember, the two lesser numbers are multiplied to find the greatest number. Here are some clues:
The first multiplication fact gives us 10, which is a lesser number. The other lesser number will help us find the greatest number. The other missing lesser number can only be 9. Now we can fill in the missing numbers.
We can also complete the second multiplication fact.
There you have it. Our multiplication family for 9, 10, and 90 is 9 x 10 = 90 and 10 x 9 = 90. Simple, isn't it?
