Divisibility Rules of 24, 25 and 26

Duration: 10 min

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Inside: a video lesson and guided study material.

Module outline

Numerical Ability & Problem Solving: Speed Mathematics and Basic Mathematics, Arithmetic, Number System, HCF LCM, Divisibility Rules, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Mixture and Alligation, Time and Work, Pipe and Cistern, Speed Time and Distance, Age Problems, Partnership, Data Interpretation, Mental Ability, Sequence and Series (Series), Powers and Exponents (Surds and Indices), Algebra, Statistics, Logarithm, Mensuration and Geometry, Permutation and Combination, Probability, Sequences and Series, Powers, Surds and Logarithms, Subject-Verb Agreement, Sentence Completion, Geometry, Sentence Structure and Correction, Data Sufficiency, Trigonometry, Measurement and Quantity Take-Off, Signal Space and Optimum Detection, Probability, Statistics, Algebra, Time and Work, Speed, Time and Distance, Data Interpretation, Combinatorics
Logical Reasoning: Series (Number and Letter Series) (Numerical Relations and Reasoning), Coding Decoding, Data Sufficiency, Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Seating Arrangements, Blood Relations, Directions (Direction Test), Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analytical Reasoning (Counting Figures Reasoning), Puzzle Solving (Puzzles), Calendar, Clock, Cubes & Dices, Logical Sequence Of Words, Venn Diagram, Data Arrangement, Inequality, Analogy, Ranking, Order and Sequence, Selection Decision Table (Decision Making), Alphabet and Word Tests, Numerical Reasoning, Number System, Averages, Mixtures and Alligation, Percentages, Series Completion, Analogy and Classification, Patterns in Two-Dimensional Figures, Coding and Decoding, Mathematical Operations, Direction Sense, Logical Deduction and Induction, Syllogisms and Venn Diagrams, Critical Reasoning, Order, Ranking and Sequence, Reading Comprehension, Profit, Loss and Discount, Constraint Puzzles, Traverse Surveying, Ratio and Proportion, Mensuration, Permutations and Combinations, Clocks and Calendars, Assembling and Grouping of Shapes, Transformation of Shapes, Three-Dimensional Patterns and Visualization, Cubes and Dice, Vocabulary, Blood Relations
General Knowledge & Current Affairs (India + Rajasthan): History, Geography, Polity, Indian Economy, Static General Knowledge, State Wise GK, GK- Current Affairs, Environment, Physics
Computer Fundamentals & Operating Systems: Basics of COA, Floating Point Rep, Digital Systems & Boolean Basics, Number Representation, Number System, Introduction to OS, File Management, Windows OS, Unix OS, Linux OS, Register Transfer and Microoperations, Virtual Memory
Computer Networks: Introduction to CN, Data Communication, DLL: Error Control, DLL: Access Control, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Application Layer, Hardware Basics, Network Security
Cyber Security: 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, Ethical Hacking
Programming (C & OOP): C Fundamentals, Control Flow, Arrays & Pointers, Functions, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Operators & Expressions, Sorting Algorithms, Java Fundamentals, Java
MS Office & Data Processing: MS Office Applications, Basics of DBMS
Internet & Web Technology: Society, Law & Ethics, Terms & Abbreviations, Keyboard Shortcuts, Emerging Tech Trends, Artificial Intelligence, Emerging Technologies, Internet Fundamentals, Website, Browser & Services, Web Design & Development, Protocols & Services, Web Publishing & Hosting, Server Side & Security

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 24, 25, and 26, taught by an instructor in a screen-capture format. The lesson begins with the rule for 24, explaining that a number is divisible by 24 if it is divisible by both 3 and 8. The instructor demonstrates this by checking the divisibility of 552, first by summing its digits (5+5+2=12) to confirm divisibility by 3, and then by performing long division by 8. The video then transitions to the rule for 25, which states that a number is divisible by 25 if its last two digits form a number divisible by 25. An example, 134,250, is used to illustrate this, with the last two digits, 50, being divisible by 25. Finally, the video covers the divisibility rule for 26, which has two parts: a number is divisible by 26 if it is divisible by both 2 and 13, or if subtracting 5 times the last digit from 2 times the rest of the number results in a multiple of 26. The instructor demonstrates this with the number 1248, showing that (124 x 2) - (8 x 5) = 208, which is 26 x 8. The video concludes with a 'Thanks for Watching' screen.

Chapters

0:00 – 2:00 00:00-02:00
The video opens with a title slide displaying 'DIVISIBILITY RULES' over a background of scattered numbers. It then transitions to a colorful, hand-drawn diagram titled 'DIVISIBILITY RULES' that illustrates rules for numbers 2 through 10. The main content begins with a slide titled 'Divisibility Rule of 24'. The on-screen text states that a number is divisible by 24 if it is divisible by 3 and by 8. Two examples are given: 552 is divisible by 3 and 8, and 552 is divisible by 3 and 8. The instructor, visible in a small window, begins to explain the rule. The instructor writes '24 = 3 x 8' on the slide to show the factorization.
2:00 – 5:00 02:00-05:00
The instructor demonstrates the divisibility rule for 24 using the number 552. He first checks divisibility by 3 by summing the digits: '5 + 5 + 2 = 12', and since 12 is divisible by 3, the rule is satisfied. He then checks divisibility by 8 using long division, writing '8)552' and performing the calculation: 8 goes into 55 six times (48), subtracting to get 7, bringing down the 2 to make 72, and 8 goes into 72 nine times (72), resulting in a remainder of 0. The instructor confirms that since 552 is divisible by both 3 and 8, it is divisible by 24. He then begins to write the number 552 again to reinforce the example.
5:00 – 9:39 05:00-09:39
The video transitions to the 'Divisibility Rule of 25'. The on-screen text explains that a number is divisible by 25 if the number formed by its last two digits is divisible by 25. An example is given: 134,250, where the last two digits are 50. The instructor writes '50' and circles it, then performs the division 25 into 50, showing it divides evenly. The video then moves to the 'Divisibility Rule of 26'. The first method states a number is divisible by 26 if it is divisible by both 2 and 13. The second method is a more complex rule: subtracting 5 times the last digit from 2 times the rest of the number gives a multiple of 26. An example is provided: 1248. The instructor calculates (124 x 2) - (8 x 5) = 248 - 40 = 208. He then shows that 208 is divisible by 26 (26 x 8 = 208). The video concludes with a 'THANKS FOR WATCHING' screen.

The video provides a clear, step-by-step tutorial on divisibility rules for three composite numbers. It follows a consistent structure: presenting the rule, providing an example, and demonstrating the verification process. The lesson progresses from a rule based on factorization (24) to a rule based on the last two digits (25), and finally to a more complex algebraic rule (26). The use of on-screen writing and a live instructor enhances the learning experience, making the mathematical concepts accessible and easy to follow.