Short Trick to find LCM of big numbers

Duration: 4 min

This video lesson is available to enrolled students.

Inside: a video lesson and guided study material.

Module outline

Quantitative Ability: Speed Mathematics and Basic Mathematics, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Pipe and Cistern, Speed Time and Distance, Number System, HCF LCM, Data Interpretation, Age Problems, Mixture and Alligation, Partnership, Algebra, Sequence and Series (Series), Mensuration and Geometry, Arithmetic
Reasoning Ability: Puzzle Solving (Puzzles), Seating Arrangements, Coding Decoding, Blood Relations, Directions (Direction Test), Syllogisms, Data Sufficiency, Ranking, Order and Sequence, Series (Number and Letter Series) (Numerical Relations and Reasoning), Logical Sequence Of Words, Calendar, Clock, Cubes & Dices, Analytical Reasoning (Counting Figures Reasoning), Data Arrangement, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning)
Verbal Ability: Comprehension / Reading Comprehension / Unseen Passages (Critical Reasoning) (Paragraph Questions), Cloze Test (Cloze Passage), Sentence Re-arrangements (Para Jumbles) (Narrative Sequencing), Vocabulary, Sentence Completion (Fill in the blanks), Active Passive Voice (Voice), Direct and Indirect Speech, Subject Verb Agreement (Verb Noun Agreement), Tenses, Preposition, Articles, Sentence Correction (Error Correction)
Programming Basics (MCQs + Interview): C Programming by Yash Sir, Programming in C++, Java, Python for Placements by Yash Sir
OOPs (MCQs + Interview): Object Oriented Programming (OOPS)
DBMS (MCQs + Interview): Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Transaction Management, Decomposition Properties & 4NF, Concurrency Control, Database Recovery, File Organization & Indexing, Relational Algebra, Database Security & Authorization
SQL (MCQs + Interview): SQL
Operating Systems (MCQs + Interview): Introduction to OS, Process Management, CPU Scheduling, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Process Synchronization, Disc Scheduling, File Management, Security
Computer Networks (MCQs + Interview): Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, 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, Mobile Technology, Cloud Computing and IoT, Cyber and Info Security
Coding: Coding Questions by Yash Sir
HR Interview: MR & HR Interview Preparation

AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video, presented by Yash Jain, is a tutorial on finding the Least Common Multiple (LCM) of numbers, specifically focusing on a method for large numbers. The video begins with an introduction to the topic, using a title card and a classroom-style animation. The core of the lesson demonstrates a step-by-step algorithm for calculating the LCM. The instructor first explains the method using the numbers 12 and 18, showing how to divide them by their common prime factors (2 and 3) to reduce them to 2 and 3, and then multiply the divisors (2 x 3) and the final quotients (2 x 3) to get the LCM of 36. The method is then applied to a more complex example with four numbers: 5, 15, 20, and 30. The instructor divides all numbers by their common prime factor 5, resulting in 1, 3, 4, and 6. The LCM of these reduced numbers is found to be 12, and the final LCM is calculated as 12 x 5 = 60. The video concludes with a 'Thanks for Watching' screen.

Chapters

0:00 – 2:00 00:00-02:00
The video opens with a title card displaying 'LCM & HCF' against a digital background. It then transitions to a classroom setting with a cartoon teacher and a live instructor, Yash Jain, in a small window. The main screen shows a green chalkboard with the title 'Least Common Common Multiple (LCM)' and the topic '7. LCM of Big Numbers'. The instructor begins the lesson by introducing the concept of LCM, which is the smallest number that is a multiple of two or more given numbers. The first example shown is 'LCM (12, 18)'. The instructor explains the method of finding the LCM by dividing the numbers by their common prime factors. The first step shown is dividing 12 and 18 by 2, resulting in 6 and 9. The instructor then divides 6 and 9 by 3, resulting in 2 and 3. The final LCM is calculated as 2 x 3 x 2 x 3 = 36.
2:00 – 4:12 02:00-04:12
The video continues with the second example, 'LCM (5, 15, 20, 30)'. The instructor demonstrates the same method. The numbers are divided by their common prime factor, 5, resulting in 1, 3, 4, and 6. The instructor then finds the LCM of these reduced numbers. The LCM of 1, 3, 4, and 6 is calculated as 12. The final LCM of the original numbers is then found by multiplying the common divisor (5) by the LCM of the reduced numbers (12), resulting in 5 x 12 = 60. The instructor emphasizes that this method is efficient for finding the LCM of large numbers. The video ends with a 'Thanks for Watching' screen.

The video provides a clear, step-by-step tutorial on a specific algorithm for calculating the Least Common Multiple (LCM) of multiple numbers, particularly useful for large numbers. The core method involves identifying a common prime factor of all the numbers, dividing them by this factor, and then recursively finding the LCM of the resulting quotients. The final LCM is the product of the common divisor and the LCM of the reduced numbers. The lesson progresses from a simple example (12, 18) to a more complex one (5, 15, 20, 30), demonstrating the method's scalability. The visual aids, including the animated classroom and the step-by-step writing on the virtual board, effectively support the explanation of this mathematical concept.