Tricks To Find Sum of Factors & Sum of Odd & Even Factors

Duration: 13 min

This video lesson is available to enrolled students.

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Inside: a video lesson and guided study material.

Module outline

  1. About the Course: About the Course
  2. Paper-1 & 2 | Basic Numeracy: अनुपात और समानुपात / Ratio and Proportion, Divisibility Rules, मिश्रण और एलिगेशन / Mixture and Alligation, Permutation and Combination, Logarithm, संख्या पद्धति / Number System, महत्तम समापवर्तक और लघुत्तम समापवर्त्य / HCF and LCM, Sequence and Series (Series), समय, चाल और दूरी / Time, Speed and Distance, प्रतिशत / Percentage, औसत / Average, घन क्षेत्रमिति / Solid Mensuration, Age Problems, Arithmetic, Statistics, Probability, लाभ, हानि और बट्टा / Profit, Loss and Discount, साधारण और चक्रवृद्धि ब्याज / Simple and Compound Interest, Partnership, Speed Mathematics and Basic Mathematics, Algebra, सरलीकरण, घातांक और करणी / Simplification, Indices and Surds, समय और कार्य / Time and Work, Pipe and Cistern, RSSB Specific Videos - Basic Numeracy, समुच्चय, संबंध, फलन और विविक्त गणित / Sets, Relations, Functions and Discrete Mathematics, संख्या पद्धति और संख्या सिद्धांत / Number Systems and Number Theory, निर्देशांक ज्यामिति, सदिश और त्रिविमीय ज्यामिति / Coordinate Geometry, Vectors and 3D Geometry, बहुपद, समीकरण और सम्मिश्र संख्याएँ / Polynomials, Equations and Complex Numbers
  3. Paper-1 & 2 | Data Interpretation: आँकड़ा निर्वचन / Data Interpretation
  4. Paper-1 & 2 | General Mental Ability: Mental Ability, RSSB Specific Videos - Mental Ability
  5. Paper-1 & 2 | Logical Reasoning and Analytical Ability: श्रेणी / Series, कूट लेखन एवं कूट वाचन / Coding-Decoding, Data Sufficiency, अशाब्दिक तर्क / Non-Verbal Reasoning, Syllogisms, बैठक व्यवस्था एवं पहेलियाँ / Seating Arrangement and Puzzles, रक्त संबंध / Blood Relations, दिशा एवं दूरी / Direction and Distance, Analytical Reasoning (Counting Figures Reasoning), गणितीय संक्रियाएँ एवं लुप्त संख्या / Mathematical Operations and Missing Numbers, कैलेंडर एवं घड़ी / Calendar and Clock, Clock, घन, पासा एवं आकृतियों की गिनती / Cubes, Dice and Figure Counting, वेन आरेख, न्याय वाक्य एवं असमानता / Venn Diagrams, Syllogism and Inequalities, सादृश्यता एवं वर्गीकरण / Analogy and Classification, क्रम एवं रैंकिंग / Order and Ranking, कथन आधारित तार्किक विवेचन / Statement-Based Reasoning, Data Arrangement, वर्णमाला एवं संख्या परीक्षण / Alphabet and Number Test, Crypt Arithmetic
  6. Paper-1 & 2 | Decision Making and Problem Solving: आँकड़ों की पर्याप्तता एवं निर्णय क्षमता / Data Sufficiency and Decision Making
  7. Paper-1 | General Science: वैज्ञानिक उपलब्धियाँ और अनुसंधान / Scientific Achievements and Research, Biology, Chemistry, RSSB Specific Videos
  8. Paper-1 | General Awareness: राज्य विशेष सामान्य ज्ञान / State-Specific General Knowledge, समसामयिकी / Current Affairs
  9. Paper-2 | Fundamentals of Computer: Basics of COA, Number System, Floating Point Rep, Number Representation
  10. Paper - 2 | Digital Logic Systems: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits
  11. Paper-2 | Operating Systems: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Linux OS, Distributed Systems
  12. Paper-2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Relational Calculus, File Organization & Indexing, Transaction Management, Concurrency Control
  13. Paper-2 | Data Structures: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing
  14. Paper-2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  15. Paper 2 | Oops, C++, Java: Language Design, OOPS with C++, Java, .Net Programming, Java Fundamentals
  16. Paper 2 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  17. Paper 2 | Emerging Trends and AI: Emerging Tech Trends, कंप्यूटर के मूल सिद्धांत / Computer Fundamentals, व्यापार, विपणन एवं उपभोक्ता संरक्षण / Trade, Marketing and Consumer Protection, कंप्यूटर नेटवर्क / Computer Networks
  18. Paper-2 | Algorithms: Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Advanced Algorithms
  19. Paper 2 | Data Communication and Network Security: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware basics, Network Security, Ethical Hacking
  20. Paper-2 I Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  21. Paper-2 | Computer Organization and Architecture: Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations
  22. Paper-2 | Web Development: JavaScript-Basics, HTML Basics, CSS, XML
  23. Pedagogy: वृद्धि और विकास / Growth and Development, Concept of Pedagogy, संज्ञानात्मक प्रक्रियाएँ / Cognitive Processes, विकास के सिद्धांत / Theories of Development, समावेशी शिक्षा / Inclusive Education, Experiential Pedagogy, समाजीकरण और जेंडर / Socialisation and Gender, National Education Policy (NEP) 2020
  24. Live Sessions: RSSB Live Sessions
  25. RSSB Paper 1 - Full Mock Tests:
  26. RSSB Paper 2 - Full Mock Tests:
  27. SCI Previous Year Papers:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video is a mathematics lecture on number systems, specifically focusing on the sum of factors. The instructor begins by introducing the topic with a title slide and then transitions to a whiteboard presentation. The core of the lesson is the derivation and application of a formula to calculate the sum of all factors of a given number. Using the number 60 as a primary example, the instructor first lists all its factors and sums them to get 168. He then demonstrates the prime factorization of 60 as 2^2 * 3^1 * 5^1. The main formula is presented: for a number N = X^a * Y^b * Z^c, the sum of its factors is [(X^(a+1) - 1)/(X - 1)] * [(Y^(b+1) - 1)/(Y - 1)] * [(Z^(c+1) - 1)/(Z - 1)]. The instructor applies this formula to 60, showing the calculation step-by-step to arrive at 168. The lesson then extends to finding the sum of odd and even factors. For the sum of odd factors, the formula is applied by excluding the prime factor 2, resulting in (3^2 - 1)/(3 - 1) * (5^2 - 1)/(5 - 1) = 24. For the sum of even factors, the instructor subtracts the sum of odd factors from the total sum of factors (168 - 24 = 144), or alternatively, factors out 2^1 from the total sum. The video concludes with a thank you message.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video starts with a title slide for 'NUMBER SYSTEM' and then transitions to a presentation slide with the same title, featuring a colorful background with mathematical symbols. The instructor, Yash Jain, appears in a small window in the bottom right corner. The slide includes the text 'The mysterious world of numbers...' and 'Basic To Advance'. The instructor introduces the topic of the number system, specifically focusing on the sum of factors, and begins to write the number 60 on the whiteboard.

  2. 2:00 – 5:00 02:00-05:00

    The instructor continues the lesson on the 'Sum of Factors'. He lists all the factors of 60: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60, and sums them to get 168. He then shows the prime factorization of 60 as 2^2 * 3^1 * 5^1. The instructor begins to write the general formula for the sum of factors of a number N = X^a * Y^b * Z^c, which is [(X^(a+1) - 1)/(X - 1)] * [(Y^(b+1) - 1)/(Y - 1)] * [(Z^(c+1) - 1)/(Z - 1)]. He explains that this formula is derived from the sum of a geometric series.

  3. 5:00 – 10:00 05:00-10:00

    The instructor applies the formula to the number 60. He substitutes the values into the formula: [(2^(2+1) - 1)/(2 - 1)] * [(3^(1+1) - 1)/(3 - 1)] * [(5^(1+1) - 1)/(5 - 1)]. He calculates each part: (8 - 1)/1 = 7, (9 - 1)/2 = 4, and (25 - 1)/4 = 6. He multiplies these results (7 * 4 * 6) to get 168, confirming the sum of factors. He then explains that the sum of odd factors can be found by excluding the prime factor 2, so the formula becomes (3^2 - 1)/(3 - 1) * (5^2 - 1)/(5 - 1) = 4 * 6 = 24. He also shows that the sum of even factors is the total sum minus the sum of odd factors: 168 - 24 = 144.

  4. 10:00 – 13:26 10:00-13:26

    The instructor concludes the lesson by summarizing the key points. He reiterates the formula for the sum of factors and its application to find the sum of odd and even factors. He emphasizes that the sum of even factors can be calculated by subtracting the sum of odd factors from the total sum of factors. The video ends with a 'Thank You for Watching' message in a neon-style graphic.

The video provides a clear, step-by-step tutorial on calculating the sum of factors of a number. It begins with a practical example, listing all factors of 60 and summing them. It then introduces the general formula derived from the sum of a geometric series, which is the most efficient method for larger numbers. The instructor demonstrates the formula's application to the same example, confirming the result. The lesson is extended to find the sum of odd and even factors, showing two methods: one by directly applying the formula to the relevant prime factors and another by using the relationship between the total sum and the sum of odd factors. This structured approach effectively teaches the concept and its applications.

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