What are the factors and factor pairs of 100?
The concept of factors of 100 plays a key role in mathematics and is widely applicable to both real-life situations and exam scenarios. Understanding the factors of 100 makes calculations with division, LCM, HCF, and multiples much easier, and helps students solve word problems quickly and accurately. Mastering this topic boosts confidence in number theory chapters, which is why practicing with factors—like those of 100—is so important for foundational maths.
What Are Factors of 100?
A factor of 100 is a whole number that divides 100 exactly, without leaving a remainder. In other words, if you multiply two whole numbers and get 100 as the result, both of those numbers are factors of 100. You’ll find this concept applied in areas such as multiples, divisibility, LCM and HCF (GCF), and when simplifying fractions in maths.
List of All Factors of 100
The complete list of factors of 100 (positive only, as commonly used in school maths) is:
- 1
- 2
- 4
- 5
- 10
- 20
- 25
- 50
- 100
These are all the numbers that divide 100 exactly—no remainder!
How to Find Factors of 100
Here are the most reliable ways to find all factors of 100, step by step:
- Start with 1 (since 1 is always a factor of every whole number).
- Check each whole number up to 100:
If 100 ÷ that number = a whole number (no remainder), it’s a factor.
- Continue until you reach 100 itself (every number is a factor of itself).
Quick List by Division:
| Divisor | 100 ÷ Divisor | Remainder | Is Factor? |
|---|---|---|---|
| 1 | 100 | 0 | Yes |
| 2 | 50 | 0 | Yes |
| 4 | 25 | 0 | Yes |
| 5 | 20 | 0 | Yes |
| 10 | 10 | 0 | Yes |
| 20 | 5 | 0 | Yes |
| 25 | 4 | 0 | Yes |
| 50 | 2 | 0 | Yes |
| 100 | 1 | 0 | Yes |
Prime Factorization of 100
Prime factorization means expressing 100 as a product of its prime numbers.
The prime factors of 100 are 2 and 5.
Here’s the step-by-step breakdown:
1. 100 ÷ 2 = 502. 50 ÷ 2 = 25
3. 25 ÷ 5 = 5
4. 5 ÷ 5 = 1
So, the prime factorization of 100 is 2 × 2 × 5 × 5, or written using exponents: 22 × 52.
Factor Pairs of 100
Factor pairs are two numbers that multiply together to give 100. Practicing factor pairs helps with area, perimeter, and word-problem questions in exams. Here’s a compact table:
| Pair # | First Factor | Second Factor | Product |
|---|---|---|---|
| 1 | 1 | 100 | 100 |
| 2 | 2 | 50 | 100 |
| 3 | 4 | 25 | 100 |
| 4 | 5 | 20 | 100 |
| 5 | 10 | 10 | 100 |
Speed Trick or Vedic Shortcut
Here’s a quick trick to check if a number is a factor of 100:
- Divide 100 by your number.
- If the result is a whole number (integer), it’s a factor.
- If you get a remainder, it is NOT a factor.
Tip: Notice that any factor of 100 will end in 0 or 5, or divide 100 evenly.
Memorizing the factor pairs and prime factorization is a favorite strategy shared in Vedantu’s live math classes to boost calculation speed during revision or exams.
Try These Yourself
- List all even factors of 100.
- Find all odd factors of 100.
- Is 8 a factor of 100?
- Write the sum of all factors of 100.
- Find the LCM and HCF of 50 and 100 (using factors).
Frequent Errors and Misunderstandings
- Assuming 8 or 3 are factors of 100 (100 ÷ 8, 100 ÷ 3 give remainders).
- Confusing factors with multiples (e.g., thinking 200 is a factor of 100—actually, 100 is a factor of 200).
- Skipping 1 or the number itself (100) as factors.
- Not pairing factors (forgetting (10,10) is a valid pair).
Relation to Other Concepts
The idea of factors of 100 connects closely with LCM and HCF, and factor trees. Mastering factors helps you easily find common divisors, reduce fractions to lowest terms, and solve word-problems about grouping or sharing.
Classroom Tip
A quick way to remember the factors of 100 is to use the rule—“If a number divides 100 with no remainder, it’s a factor.” Make a table or color the factors in a number chart for fast visual learning. Vedantu’s teachers often use real-life objects (like 100 rupees) to show all possible groups, making maths practical and fun!
We explored factors of 100—from definitions, factor pairs, prime factorization, and mistakes, to how they relate to other maths topics. Continue practicing with Vedantu to become confident in solving problems using this concept, and try linking factors to everyday numbers you use!
Related Vedantu Resources
FAQs on Factors of 100: Complete Concept Explanation & Methods
1. What are the factors of 100?
The factors of 100 are the whole numbers that divide 100 exactly without leaving a remainder. These are: 1, 2, 4, 5, 10, 20, 25, 50, and 100.
2. How many factors does 100 have?
The number 100 has nine factors.
3. What are the factor pairs of 100?
The factor pairs of 100 are pairs of numbers that multiply to 100. They are: (1, 100), (2, 50), (4, 25), (5, 20), and (10, 10).
4. What is the prime factorization of 100?
The prime factorization of 100 is 22 × 52. This means 100 can be written as the product of its prime factors: 2 × 2 × 5 × 5.
5. How do I find the factors of 100 using the division method?
To find the factors using the division method, successively divide 100 by integers starting from 1. If the division results in a remainder of 0, the divisor is a factor. Continue until the quotient becomes less than the divisor.
6. What are the odd factors of 100?
The odd factors of 100 are 1, 5, and 25. These are the factors that are not divisible by 2.
7. What are the even factors of 100?
The even factors of 100 are 2, 4, 10, 20, 50, and 100. These are the factors that are divisible by 2.
8. What is the sum of the factors of 100?
The sum of the factors of 100 is 1 + 2 + 4 + 5 + 10 + 20 + 25 + 50 + 100 = 217
9. How are factors of 100 used in finding the Highest Common Factor (HCF)?
To find the HCF of 100 and another number, list the factors of both numbers. The greatest factor that is common to both lists is the HCF.
10. How are factors of 100 used in finding the Lowest Common Multiple (LCM)?
The factors of 100 help in finding the LCM. One method involves using the prime factorization of 100 and the other number to find the LCM.
11. Are negative numbers considered factors of 100?
While typically only positive factors are considered in elementary mathematics, -1, -2, -4, -5, -10, -20, -25, -50, and -100 are also factors of 100 because they divide 100 without leaving a remainder.
12. What are some real-life examples where understanding factors of 100 is useful?
Understanding factors is useful in various real-life situations, such as dividing 100 items equally among a number of people, calculating areas of rectangles with an area of 100 square units, or solving problems involving ratios and proportions.
