Related Facts – Definition With Examples

What Are Related Facts

Related facts in Math are facts that are related to each other in some way. We can easily find related facts using the given facts. 

Since addition and subtraction are inverse operations, we can form their related facts. Let’s go through a related fact example:

So, A, B, and C are related facts of the given fact, $3 + 4 = 7$. 

Notice that the numbers involved in all three related facts are the same as the numbers involved in the given fact. Only the position and operation changes. 

Since multiplication and division are also inverse operations, we can form related facts for them as well.

Fact Families

Fact families are sets of addition and subtraction facts or multiplication and division facts that involve the same numbers. In other words, it is a collection of related facts. Fact families are of two types:

1. Addition and Subtraction
2. Multiplication and Division

Addition and Subtraction Fact Family

Addition and subtraction are inverse operations. If we first add a number to a given number and then subtract the same number from the result, we get the original number back. For example, consider 10 as the given number, we add and subtract 2.

$10 + 2 = 12$

$12 – 2 = 10$ (original number)

This means that these two operations cancel each other’s effect on another number or expression. 

Let’s have a look at some fact families of addition and subtraction. 

We can assume that fact families are like parts of a whole, where the largest number is the whole, and the other two numbers are the two parts that make up the whole. In the first example above, 10 is the whole and the numbers 4 and 6 are the parts.

Multiplication and Division Fact Families

We know that multiplication and division are also inverse operations, so we can form fact families for these two operations using the related facts. Let’s have a look at some fact families of multiplication and division. 

Importance of Related Facts

Related facts are used so that a student can understand the relationships between the operations of addition and subtraction, and multiplication and division. It helps the students to remember that addition and subtraction are inverse operations and multiplication and division are inverse operations.

For example, if we know any one fact from a fact family, we can easily find the other related facts. 

Solved Examples

Example 1: Identify which family the given numbers belong to. Also write all four related facts. 

Solution: 

Let’s try adding the two smaller numbers, $9 + 8 = 17$ (third number)

So, these numbers belong to the addition and subtraction fact family. 

The other related facts are: 

$8 + 9 = 17$

$17 － 8 = 9$

$17 － 9 = 8$

Example 2: Identify which fact family the given numbers belong to. Also write all four related facts. 

Solution: 

Let’s try adding the two smaller numbers, $5 + 7 = 12 ≠ 35$. 

Now let’s multiply these numbers. 

$5 \times 7 = 35$ (third number)

So, these numbers belong to the multiplication and division fact family. 

The other related facts are: 

$7 \times 5 = 35$

$35 \div 5 = 7$

$35 \div 7 = 5$

Example 3: Use the given fact to complete the fact family. 

Solution: It is given that $10 – 3 = 7$. 

Using this fact, we can easily determine the other related facts. 

Example 4: Make a fact family of 2, 8 and 16.

Solution: 2, 8 and 16 belong to the multiplication and division fact family. 

Example 5: One of the facts is given: $5 ☐ 3 = 15$. Identify the operation and write all other related facts. 

Solution: $5 \times 3 = 15$. 

The other related facts are: 

$3 \times 5 = 15$

$15 \div 3 = 5$

#$15 \div 5 = 3$

Practice Problems

Frequently Asked Questions