Divisibility Rules of Important Numbers From 31 to 1000

Duration: 6 min

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Module outline

  1. About Course: About the Course
  2. General Aptitude & Reasoning: Number System, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Speed Time and Distance, Mixture and Alligation, Data Interpretation, Algebra, Probability, Permutation and Combination, Venn Diagram, HCF LCM, Divisibility Rules, Age Problems, Pipe and Cistern, Partnership, Linear Algebra, Sequence and Series (Series), Statistics, Powers and Exponents (Surds and Indices), Arithmetic, Mensuration and Geometry, Calculus, Trigonometry, Vectors, Speed Mathematics and Basic Mathematics, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analogy, Series (Number and Letter Series) (Numerical Relations and Reasoning), Puzzle Solving (Puzzles), Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Calendar, Seating Arrangements, Coding Decoding, Blood Relations, Directions (Direction Test), Clock, Analytical Reasoning (Counting Figures Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Inequality, Data Sufficiency, Cubes & Dices
  3. Computer Networks & Cybersecurity: 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
  4. Programming, Data Structures & Algorithms: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  5. AI, Machine Learning, Big Data & Cloud: Emerging Tech Trends, Artificial Intelligence, Big Data Systems, Approaches to AI, Search Algorithms, Knowledge Representation, Cloud Computing
  6. Digital Logic & Computer Organization: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. TOC & Compiler: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  8. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
  9. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Distributed Systems
  10. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Object Oriented Technology, HTML Basics, JavaScript-Basics, Java, XML
  11. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Data Warehousing & Mining, Enhanced Data Models, NoSQL
  12. Other Recurring CS Topics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, Multimedia
  13. Live Classes: ISRO Live classes
  14. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video provides a comprehensive overview of divisibility rules for various numbers, presented by an instructor from Knowledge Gate Eduventures. The lecture begins with a title slide and a colorful, circular diagram summarizing rules for divisors 2 through 10. The main content consists of a detailed table that systematically lists divisibility rules for divisors from 31 to 99. For each divisor, the video explains a specific condition, such as 'Subtract three times the last digit from the rest' for 31, and provides a worked example. The instructor uses a digital whiteboard to demonstrate the application of these rules, for instance, showing how to test 837 for divisibility by 31. The video concludes with a final slide that thanks the viewer, summarizing the extensive list of rules covered.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title slide displaying 'DIVISIBILITY RULES' over a background of scattered numbers. This transitions to a colorful, hand-drawn circular diagram that visually organizes divisibility rules for divisors 2 through 10, with examples like '2: (is an even number)' and '3: the sum of the digits is divisible by 3'. The instructor, Yash Jain Sir, appears in a small window, introducing the topic. The scene then shifts to a digital whiteboard where the instructor begins writing, starting with the number 31 and the word 'prime', setting the stage for the detailed rules to follow.

  2. 2:00 – 5:00 02:00-05:00

    The video presents a detailed table of divisibility rules. The instructor explains the rule for 31: 'Subtract three times the last digit from the rest', demonstrated with the example 837, where 83 - (3x7) = 62. The rule for 32 is shown as 'The number formed by the last five digits is divisible by 32', with an example of 25,135,520. The rule for 33 is 'Add 10 times the last digit to the rest', illustrated with 627, where 62 + (10x7) = 132. The instructor continues to explain the rule for 35: 'It is divisible by 3 and by 11', using the example 627, where the sum of digits (6+2+7=15) is divisible by 3, and the alternating sum (6-2+7=11) is divisible by 11. The table also shows rules for 37, 39, and 41, with the instructor explaining the rule for 41: 'Sum the digits in blocks of five from right to left', using 72,841,536,727 as an example.

  3. 5:00 – 6:03 05:00-06:03

    The video continues with the table of divisibility rules, showing the rule for 43: 'Add 13 times the last digit to the rest', with the example 3629, where 362 + (13x9) = 3741. The rule for 47 is 'Subtract 14 times the last digit from the rest', demonstrated with 1,642,979, where 1,642,97 - (14x9) = 16403. The rule for 49 is 'Add 5 times the last digit to the rest', shown with 705, where 70 + (5x5) = 95. The video then shows the rule for 51: 'Number must be divisible by 3 and 17', with the example 459, where 4+5+9=18 is divisible by 3, and 45-9=36 is divisible by 17. The final rule shown is for 99: 'Number is divisible by 9 and 11', with the example 891, where 8+9+1=18 is divisible by 9, and 8-9+1=0 is divisible by 11. The video ends with a 'THANKS FOR WATCHING' slide.

The video systematically teaches a series of advanced divisibility rules, moving from a general overview to a detailed, table-based presentation. The core teaching method involves a clear, structured table that pairs each divisor with a specific, often non-intuitive, rule and a concrete example. The instructor's use of a digital whiteboard to demonstrate the application of these rules, such as the step-by-step calculation for 837 ÷ 31, reinforces the practical application of the concepts. The progression from simpler rules (like 2, 3, 5) to more complex ones (like 31, 43, 99) provides a logical learning path, culminating in a comprehensive reference guide for divisibility testing.

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