Divisibility Rules of 28, 29, 30 and 31

Duration: 10 min

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Module outline

  1. About the course: About the Course
  2. General Knowledge: Polity, Physics, Biology, State Wise GK, Chemistry, History, Geography, GK- Current Affairs, Indian Economy, Static General Knowledge, Environment, Evolution of Indian Banking (Banking & Financial Awareness)
  3. Mental Aptitude and Reasoning: Ratio and Proportion (Ratios), Divisibility Rules, Data Interpretation, Permutation and Combination, Number System, Sequence and Series (Series), Speed Time and Distance, Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Vocabulary, Profit and Loss, Arithmetic, Mental Ability, Percentage, Algebra, Mensuration and Geometry, Age Problems, Clock, Calendar, Verbal Analogy (Word Based Analogy), Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Analogy, Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Selection Decision Table (Decision Making), Cubes & Dices, Blood Relations, Venn Diagram, Logical Sequence Of Words, Inequality, Directions (Direction Test), Data Arrangement, Facts, Inference and Judgements, Syllogisms, Seating Arrangements, Ranking, Order and Sequence
  4. CS | Computer Fundamentals: Basics of COA, Number System, Number Representation, C Fundamentals, Algorithm Analysis, Input Output Organisation
  5. CS | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, SQL
  6. CS | Workplace productivity Tools: MS Office Applications, Keyboard Shortcuts
  7. CS | Computer Networks: Introduction to CN, Data Communication, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Transport Layer Services, Application Layer, Hardware Basics, Network Security
  8. CS | The Internet: Website, Browser & Services, Internet Fundamentals, Web Design & Development, Web Publishing & Hosting, Server Side & Security, Emerging Technologies
  9. CS | Emerging Technologies: Artificial Intelligence, Emerging Tech Trends, Introduction to OS, Windows OS, Linux OS, Unix OS, JavaScript-Basics
  10. CS | Boolean algebra: Digital Systems & Boolean Basics, Boolean Expression, Boolean Minimization, Logic Gates & Hardware
  11. CS | Data Structures: Introduction to DS, Array, Stack, Queue
  12. CS | Cryptography: Society, Law & Ethics, Cyber Threats and Malware Attacks, Role of Internet and Web Services, Security in Mobile and Wireless Computing, Electronic Data Interchange and E-Commerce, Physical Security and Cryptography Basics, Intrusion Detection Systems (IDS), Cyber Safety and Security
  13. UP Police Previous Year Papers:
  14. UP Police Full Mock Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This educational video presents a series of divisibility rules for the numbers 28, 29, 30, and 31, taught by an instructor named Yash Jain Sir. The video begins with a title card and a colorful, hand-drawn diagram illustrating various divisibility rules. The main content consists of four distinct slides, each dedicated to a specific number. For 28, the rule is that a number is divisible by 28 if it is divisible by both 4 and 7, with the example of 140 being used. For 29, the rule is to add three times the last digit to the remaining leading truncated number, and if the result is divisible by 29, then so is the original number, demonstrated with the example 15689. For 30, the rule is that a number must be divisible by both 3 and 10, illustrated with the example 270. Finally, for 31, the rule is to subtract three times the last digit from the remaining leading truncated number, with the example 7998 being shown. The video concludes with a 'Thanks for Watching' screen.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title card displaying 'DIVISIBILITY RULES' over a background of scattered numbers. This transitions to a colorful, hand-drawn diagram titled 'DIVISIBILITY RULES' which visually explains rules for numbers 2, 3, 4, 5, 6, 7, 8, 9, 10, and 11. The instructor, Yash Jain Sir, appears in a small window in the bottom right corner. The first main slide is then shown, titled 'Divisibility Rule of 28'. It states that a number is divisible by 28 if it is divisible by 4 and by 7, with the example 140. The instructor begins to explain the rule, and the number 28 is written as 4 x 7 on the slide.

  2. 2:00 – 5:00 02:00-05:00

    The video continues to focus on the 'Divisibility Rule of 28'. The instructor explains that since 28 = 4 x 7, a number must be divisible by both 4 and 7. He demonstrates this with the example 140. He shows that 140 divided by 4 is 35, and 140 divided by 7 is 20. He also writes the multiplication 28 x 5 = 140 to reinforce the concept. The slide remains on screen, and the instructor's voiceover explains the logic behind the rule, emphasizing that if a number is divisible by two co-prime numbers, it is divisible by their product.

  3. 5:00 – 10:00 05:00-10:00

    The video transitions to a new slide titled 'Test for divisibility by 29'. The rule is stated: 'Add three times the last digit to the remaining leading truncated number. If the result is divisible by 29, then so was the first number.' An example is provided: 15689. The instructor demonstrates the process step-by-step: 1568 + 3*9 = 1568 + 27 = 1595. He continues: 159 + 3*5 = 159 + 15 = 174. Then: 17 + 3*4 = 17 + 12 = 29. Since 29 is divisible by 29, the original number 15689 is also divisible by 29. The video then moves to the 'Divisibility Rule of 30', stating it is divisible by 3 and 10, with the example 270. Finally, it presents the 'Test for divisibility by 31', which is to 'Subtract three times the last digit from the remaining leading truncated number.' The example 7998 is used: 799 - 3*8 = 799 - 24 = 775. Then: 77 - 3*5 = 77 - 15 = 62. Since 62 is 2*31, 7998 is divisible by 31.

  4. 10:00 – 10:05 10:00-10:05

    The video concludes with a final screen. The background is a dark purple gradient. In the center, the text 'THANKS FOR WATCHING' is displayed in a large, white, sans-serif font. This is the end of the lecture.

The video provides a clear and structured lesson on advanced divisibility rules. It follows a consistent pattern: introducing a rule for a specific number, explaining the logic (often by breaking the number into its prime factors), and then demonstrating the rule with a detailed, step-by-step example. The use of a hand-drawn diagram at the beginning provides context, while the subsequent slides focus on one rule at a time, ensuring clarity. The progression from 28 to 31 is logical, covering a range of composite numbers and demonstrating different types of rules (multiplication, addition, subtraction). The instructor's methodical approach makes the concepts accessible for students preparing for competitive exams.

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