Concept of Reminders (Part 1)

Duration: 13 min

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AI Summary

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This educational video is a mathematics lecture focused on the concept of remainders in number systems, presented by an instructor named Yash Jain from Knowledge Gate. The video begins with a title slide introducing the topic. It then transitions to a lesson on the 'Concept of Remainders,' using a visual analogy of two dogs sharing bones to explain that 7 divided by 2 equals 3 with a remainder of 1, which is written as 7 ÷ 2 = 3 R1. The core of the video consists of two worked examples. The first problem asks for the remainder when N = 1421 * 1423 * 1425 is divided by 12. The instructor demonstrates a method where each number in the product is divided by 12 to find its remainder (1421 ÷ 12 gives remainder 5, 1423 ÷ 12 gives remainder 7, and 1425 ÷ 12 gives remainder 9), and then the product of these remainders (5 * 7 * 9) is calculated. The final step is to find the remainder of this product when divided by 12, which is 3. The second problem is to find the remainder when P = 1719 * 1721 * 1723 * 1725 * 1727 is divided by 18. The same method is applied: find the remainder of each number when divided by 18 (9, 11, 13, 15, 17), multiply them, and then find the remainder of the product when divided by 18, which is 9. The video concludes with a 'Thank You for Watching' screen.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video opens with a title slide displaying 'NUMBER SYSTEM' in a stylized font against a grey gradient background. This transitions to a colorful presentation slide with the title 'NUMBER SYSTEM' and the subtitle 'The mysterious world of numbers...'. The slide features various mathematical symbols and a red box in the top right corner with the text '- by YASH [KG]'. A picture-in-picture of the instructor, Yash Jain, appears in the bottom right corner. The slide also includes text identifying him as a 'Knowledge Gate Educator' and the content as 'Basic To Advance'. The instructor begins the lecture, introducing the topic of number systems.

  2. 2:00 – 5:00 02:00-05:00

    The video displays a slide titled 'Concept of Remainders'. The instructor uses a visual analogy of two dogs and bones to explain the concept. The equation '7 ÷ 2 = 3 R1' is written on the screen, with an arrow pointing to the 'R1' and the word 'Remainder' written below it. The instructor explains that when 7 is divided by 2, the quotient is 3 and the remainder is 1. He then begins to write the first problem on the screen: 'Q: Let N = 1421 * 1423 * 1425. What is the remainder when N is divided by 12?'. He starts to solve it by writing '1421 ÷ 12' and begins the long division process.

  3. 5:00 – 10:00 05:00-10:00

    The instructor continues solving the first problem. He completes the long division for 1421 ÷ 12, showing that the remainder is 5. He then applies the same process to 1423 ÷ 12, finding a remainder of 7, and 1425 ÷ 12, finding a remainder of 9. He writes the equation '5 * 7 * 9' and calculates the product, which is 315. He then performs the final step: 315 ÷ 12, and shows that the remainder is 3. He circles the final answer, 3, and explains that this is the remainder of the original product N when divided by 12. He then moves to the second problem.

  4. 10:00 – 13:26 10:00-13:26

    The video presents the second problem: 'Q: Consider a number P = 1719 * 1721 * 1723 * 1725 * 1727. Find the remainder when P is divided by 18?'. The instructor begins solving it by finding the remainder of each number when divided by 18. He shows that 1719 ÷ 18 gives a remainder of 9, 1721 ÷ 18 gives 11, 1723 ÷ 18 gives 13, 1725 ÷ 18 gives 15, and 1727 ÷ 18 gives 17. He writes the product of these remainders: '9 * 11 * 13 * 15 * 17'. He then calculates the product step-by-step, first 9 * 11 = 99, then 99 * 13 = 1287, and so on, until he gets the final product. He then divides this large product by 18 to find the remainder, which he calculates to be 9. He circles the answer 9. The video ends with a 'Thank You for Watching' screen.

The video provides a clear, step-by-step tutorial on finding the remainder of a product of numbers when divided by a given divisor. The central method demonstrated is that the remainder of a product is equal to the remainder of the product of the individual remainders. This is a powerful shortcut for problems involving large numbers. The instructor uses a consistent and logical approach: first, find the remainder of each factor when divided by the divisor; second, multiply these remainders together; third, find the remainder of this final product when divided by the divisor. The lecture is structured with a simple analogy to introduce the concept, followed by two progressively more complex examples that reinforce the method. The visual aids, including the use of a digital whiteboard for calculations, make the process easy to follow.