What is a multiple What is LCM Find LCM by inspection

Duration: 11 min

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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 | Digital Logic Systems: Digital Systems & Boolean Basics, Logic Gates & Hardware, Combinational Circuit, Sequential Circuits
  10. Paper-2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Calculus, Relational Algebra, SQL, NoSQL
  11. Paper-2 | Data Structures & Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Algorithm Analysis, Sorting Algorithms, Intro to Compilers, Hashing
  12. Paper 2 | Data Communication and Network Security: Introduction to CN, Data Communication, Data Link Layer - Ethernet, DLL: Error Control, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Application Layer, Hardware basics, Network Security, Ethical Hacking
  13. Paper-2 | Operating Systems: Introduction to OS, Process Management, Memory Management, File Management, Deadlock
  14. Paper-2 | Computer Organization and Architecture: Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Instr Formats & Modes, Control Unit Design, Register Transfer and Microoperations, Programming the Basic Computer, Number System, Number Representation
  15. Paper 2 | System Analysis and Design: Fundamentals of Systems and Information Systems, Fundamentals of Software Engineering, SDLC and Development Approaches, Software Documentation and Software Requirements Specification (SRS), SDD and Quality Assurance, Security, Risk Management & Maintenance, Software Testing
  16. Paper-2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  17. Paper 2 | OOPS , C++ , JAVA: Language Design, OOPS with C++, Java, .Net Programming, Java Fundamentals
  18. 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
  19. Emerging Trends and AI: Emerging Tech Trends, कंप्यूटर के मूल सिद्धांत / Computer Fundamentals, व्यापार, विपणन एवं उपभोक्ता संरक्षण / Trade, Marketing and Consumer Protection
  20. Paper-2 | Data Processing (Ms-Office): MS Office Applications, कंप्यूटर सॉफ़्टवेयर / Computer Software, ऑपरेटिंग सिस्टम / Operating System, वर्ड प्रोसेसिंग (MS Word) / Word Processing (MS Word), प्रेज़ेंटेशन (MS PowerPoint) / Presentation Software (MS PowerPoint)
  21. Paper-2 | Internet and Web Technologies: HTML Basics, CSS, XML, JavaScript-Basics, Internet Fundamentals, Protocols & Services, Web Publishing & Hosting, Server Side & Security, Emerging Technologies, Terms & Abbreviations, Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, साइबर सुरक्षा / Cyber Safety and Security, कंप्यूटर नेटवर्क / Computer Networks
  22. Paper 2 | Pedagogy: वृद्धि और विकास / Growth and Development, विकास के सिद्धांत / Theories of Development, Concept of Pedagogy, समावेशी शिक्षा / Inclusive Education, Experiential Pedagogy, आकलन और मूल्यांकन / Assessment and Evaluation, संज्ञानात्मक प्रक्रियाएँ / Cognitive Processes, समाजीकरण और जेंडर / Socialisation and Gender, National Education Policy (NEP) 2020
  23. Live Classes: RSSB Live Sessions
  24. Paper 1 - Full Mock Tests:
  25. Paper 2 - Full Mock Tests:
  26. BCI Previous Year Papers:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a comprehensive lesson on the concepts of Least Common Multiple (LCM) and Highest Common Factor (HCF), presented by an instructor named Yash Jain. The video begins with an introduction to the topic, followed by a clear definition of a 'multiple' as a number that can be divided by another number without a remainder. It then contrasts this with 'factors', explaining that a factor divides a number, while a multiple is divided by a number. The core of the lesson focuses on the method of finding the LCM by inspection, which involves listing the multiples of each number and identifying the smallest common multiple. This method is demonstrated with examples, such as finding the LCM of 5, 7, and 10, which is determined to be 70. The video also introduces the concept of LCM by prime factorization, using the numbers 5, 15, 20, and 30 as an example, where the LCM is found to be 60. The lesson concludes with a key takeaway: the LCM is always greater than or equal to the largest number in the set. The presentation uses a digital whiteboard with handwritten text and diagrams, and includes a small video feed of the instructor.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title card displaying 'LCM & HCF' against a digital background of floating numbers. It then transitions to a classroom setting with a cartoon teacher and a green chalkboard. The instructor, Yash Jain, introduces the topic of 'Least Common Multiple (LCM)' and begins to explain the concept. The on-screen text clearly states 'Least Common Multiple (LCM)' and the instructor's name is visible. The visual style is a mix of animation and a live video feed of the instructor.

  2. 2:00 – 5:00 02:00-05:00

    The video focuses on defining a 'multiple'. The on-screen text asks 'What is a multiple?'. The instructor explains that a multiple of a number is the product of that number and an integer. He provides examples, writing '5 = 5, 10, 15, 20, 25, 30, 35...' and '7 = 7, 14, 21, 28, 35, 42, 49, 56, 63, 70...'. The video then contrasts 'factors' and 'multiples', stating that a 'Factor divides the number' and a 'Multiple is divided by the number'. Examples for the number 12 are used to illustrate this difference, showing its factors {1, 2, 3, 4, 6, 12} and its multiples {12, 24, 36, 48...}. The instructor also notes that factors are always less than or equal to the number, while multiples are greater than or equal to the number.

  3. 5:00 – 10:00 05:00-10:00

    The video explains the method for finding the LCM by inspection. The on-screen text asks 'What is Least Common Multiple (LCM)?'. The instructor demonstrates this by listing the multiples of 5, 7, and 10. He circles the common multiples, such as 70, and identifies the smallest one, concluding that LCM(5, 7, 10) = 70. The video then introduces the second method, 'LCM by Inspection' for the numbers 5, 15, 20, and 30. The instructor lists the multiples of each number, circles the common ones (60, 120, 180...), and identifies the smallest, stating that LCM(5, 15, 20, 30) = 60. A key point is highlighted: 'LCM is always greater than or equal to the largest number'.

  4. 10:00 – 10:43 10:00-10:43

    The video concludes with a final summary slide. The instructor reiterates the key point that the LCM is always greater than or equal to the largest number in the set, with the equation 'LCM ≥ 30' shown for the example of 5, 15, 20, and 30. The video ends with a 'THANKS FOR WATCHING' message on a black background, signaling the end of the lesson.

The video presents a structured and clear lesson on LCM and HCF, starting with foundational definitions and progressing to practical problem-solving methods. It effectively uses visual aids like a digital whiteboard to illustrate concepts such as listing multiples and identifying common values. The core teaching method demonstrated is 'LCM by inspection', which is shown to be a reliable technique for finding the least common multiple of a set of numbers. The lesson is well-organized, moving from basic definitions to worked examples, and concludes with a key takeaway that reinforces the relationship between the LCM and the numbers involved.

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