102 LearnersLast updated on May 26th, 2025
Factors of 399
Factors are the numbers that divide any given number evenly without remainder. In daily life, we use factors for tasks like sharing items equally, arranging things, etc. In this topic, we will learn about the factors of 399, how they are used in real life, and the tips to learn them quickly.
What are the Factors of 399?
The numbers that divide 399 evenly are known as factors of 399.
A factor of 399 is a number that divides the number without remainder.
The factors of 399 are 1, 3, 7, 19, 21, 57, 133, and 399.
Negative factors of 399: -1, -3, -7, -19, -21, -57, -133, and -399.
Prime factors of 399: 3, 7, and 19.
Prime factorization of 399: 3 × 7 × 19.
The sum of factors of 399: 1 + 3 + 7 + 19 + 21 + 57 + 133 + 399 = 640
How to Find Factors of 399?
Factors can be found using different methods. Mentioned below are some commonly used methods:
- Finding factors using multiplication
- Finding factors using division method
- Prime factors and Prime factorization
Finding Factors Using Multiplication
To find factors using multiplication, we need to identify the pairs of numbers that are multiplied to give 399. Identifying the numbers which are multiplied to get the number 399 is the multiplication method.
Step 1: Multiply 399 by 1, 399 × 1 = 399.
Step 2: Check for other numbers that give 399 after multiplying
3 × 133 = 399
7 × 57 = 399
19 × 21 = 399
Therefore, the positive factor pairs of 399 are: (1, 399), (3, 133), (7, 57), (19, 21).
All these factor pairs result in 399.
For every positive factor, there is a negative factor.
Finding Factors Using Division Method
Dividing the given numbers with the whole numbers until the remainder becomes zero and listing out the numbers which result as whole numbers as factors. Factors can be calculated by following a simple division method
Step 1: Divide 399 by 1, 399 ÷ 1 = 399.
Step 2: Continue dividing 399 by the numbers until the remainder becomes 0.
399 ÷ 1 = 399
399 ÷ 3 = 133
399 ÷ 7 = 57
399 ÷ 19 = 21
Therefore, the factors of 399 are: 1, 3, 7, 19, 21, 57, 133, 399.
Prime Factors and Prime Factorization
The factors can be found by dividing it with prime numbers. We can find the prime factors using the following methods:
- Using prime factorization
- Using factor tree
Using Prime Factorization: In this process, prime factors of 399 divide the number to break it down in the multiplication form of prime factors till the remainder becomes 1.
399 ÷ 3 = 133
133 ÷ 7 = 19
19 ÷ 19 = 1
The prime factors of 399 are 3, 7, and 19.
The prime factorization of 399 is: 3 × 7 × 19.
Factor Tree
The factor tree is the graphical representation of breaking down any number into prime factors. The following step shows
Step 1: Firstly, 399 is divided by 3 to get 133.
Step 2: Now divide 133 by 7 to get 19. Here, 19 is the smallest prime number, that cannot be divided anymore.
So, the prime factorization of 399 is: 3 × 7 × 19.
Factor Pairs: Two numbers that are multiplied to give a specific number are called factor pairs. Both positive and negative factors constitute factor pairs.
Positive factor pairs of 399: (1, 399), (3, 133), (7, 57), and (19, 21).
Negative factor pairs of 399: (-1, -399), (-3, -133), (-7, -57), and (-19, -21).
Common Mistakes and How to Avoid Them in Factors of 399
Mistakes are common while finding factors. We can identify and correct those mistakes using the following common mistakes and the ways to avoid them.
Mistake 1
Forgetting the number itself and 1 is a factor
Children might forget to add the given number itself and 1 as a factor. The number itself and 1 are the factors for every whole number. Always remember to include 1 and the number itself.
For example, in factors of 399, 1 and 399 are also factors.
Factors of 399 Examples
Problem 1
There are 399 apples and 3 baskets. How will they distribute them equally?
They will get 133 apples each.
Explanation
To distribute the apples equally, we need to divide the total apples by the number of baskets.
399/3 = 133
Problem 2
A garden is rectangular, the length of the garden is 19 meters and the total area is 399 square meters. Find the width?
21 meters.
Explanation
To find the width of the garden, we use the formula, Area = length × width 399 = 19 × width
To find the value of width, we need to shift 19 to the left side.
399/19 = width
Width = 21.
Problem 3
There are 7 cars and 399 passengers. How many passengers will be in each car?
Each car will have 57 passengers.
Explanation
To find the passengers in each car, divide the total passengers by the number of cars.
399/7 = 57
Problem 4
In a class, there are 399 students, and 19 groups. How many students are there in each group?
There are 21 students in each group.
Explanation
Dividing the students by the total groups, we will get the number of students in each group.
399/19 = 21
Problem 5
399 books need to be arranged in 3 shelves. How many books will go on each shelf?
Each of the shelves has 133 books.
Explanation
Divide total books by shelves.
399/3 = 133
FAQs on Factors of 399
1.What are the factors of 399?
2.Mention the prime factors of 399.
3.Is 399 a multiple of 7?
4.Mention the factor pairs of 399?
5.What is the square of 399?
6.How can children in India use numbers in everyday life to understand Factors of 399?
7.What are some fun ways kids in India can practice Factors of 399 with numbers?
8.What role do numbers and Factors of 399 play in helping children in India develop problem-solving skills?
9.How can families in India create number-rich environments to improve Factors of 399 skills?
Important Glossaries for Factors of 399
- Factors: The numbers that divide the given number without leaving a remainder are called factors. For example, the factors of 399 are 1, 3, 7, 19, 21, 57, 133, and 399.
- Prime factors: The factors which are prime numbers. For example, 3, 7, and 19 are prime factors of 399.
- Factor pairs: Two numbers in a pair that are multiplied to give the original number are called factor pairs. For example, the factor pairs of 399 are (1, 399), (3, 133), etc.
- Multiplication method: A method to find factors by identifying pairs of numbers that multiply to give the original number.
- Division method: A method to find factors by dividing the number by whole numbers to see which ones result in a remainder of zero.
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Hiralee Lalitkumar Makwana
About the Author
Hiralee Lalitkumar Makwana has almost two years of teaching experience. She is a number ninja as she loves numbers. Her interest in numbers can be seen in the way she cracks math puzzles and hidden patterns.
Fun Fact
: She loves to read number jokes and games.
