Basics of Number System Part-2
Duration: 7 min
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AI Summary
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The lecture begins by introducing fundamental number systems used in computing and mathematics, specifically Binary, Octal, Hexadecimal, Unary, and Decimal. A table is displayed listing the "Base or Radix" and "Digits or symbols" for each system. The instructor then provides a formal definition of a number system as an ordered set of symbols ranging from 0 to r-1, where r is the base. He explains the structure of numbers containing both integer and fractional parts separated by a radix point. The session concludes with a detailed breakdown of the Decimal Number System, demonstrating how to expand a number into a sum of coefficients multiplied by powers of 10, using examples like 749.52 and 721.74 to illustrate the concept of weighted values.
Chapters
0:00 – 2:00 00:00-02:00
The instructor starts by displaying a comprehensive table comparing different number systems. The first section lists Binary (Base 2, digits 0,1), Octal (Base 8, digits 0-7), and Hexadecimal (Base 16, digits 0-9, A-F). He then points to a second table below it featuring Unary (Base 1, digits 0/1) and Decimal (Base 10, digits 0-9). He actively engages with the content by circling the base "10" for the Decimal system and "1" for the Unary system. He also writes "16" in the top right corner of the slide and points to the specific symbols used, emphasizing the range of digits available in each system.
2:00 – 5:00 02:00-05:00
The lecture moves to a text-based slide defining a number system formally. The text states it is an ordered set of symbols called digits, from 0 to r-1, if r is the base or radix. The instructor writes "(0 1 2 ... 9)10" on the screen to visualize the digit range for base 10. He emphasizes the rule that one cannot use a digit higher than r-1 in base r. He then introduces the general mathematical representation of a number with a decimal point: $(a_{n-1} a_{n-2} ... a_1 a_0 . a_{-1} a_{-2} ... a_{-m})$. He writes "749.52" as a practical example and draws brackets to separate the integer part from the fractional part, explaining the role of the radix point.
5:00 – 6:51 05:00-06:51
The final segment focuses specifically on the Decimal Number System. A slide explains that it is a base-10 system using ten digits (0-9) where coefficients are multiplied by powers of 10. The instructor provides an example $(7,392)_{10}$ and expands it into $7 * 10^3 + 3 * 10^2 + 9 * 10^1 + 2 * 10^0$. He then generalizes this for numbers with decimal points, writing "721.74" on the board. He expands this number into $7*10^2 + 2*10^1 + 1*10^0 + 7*10^{-1} + 4*10^{-2}$. Finally, he calculates the individual terms ($700 + 20 + 1 + 0.7 + 0.04$) to show how they sum back to the original number, reinforcing the concept of positional weighting.
The video serves as an introductory lesson on number systems, establishing the relationship between a base and its available digits. It progresses from a comparative overview of common systems like Binary and Hexadecimal to a formal definition involving the variable 'r' for base. The core pedagogical goal is to teach the concept of positional notation, where the value of a digit is determined by its position relative to the radix point. This is solidified through the detailed expansion of decimal numbers, showing how integer and fractional parts correspond to positive and negative powers of the base, respectively.