1. A+ Computer Repair Lesson 3: Number System

2. Objectives Define binary, decimal, octal, and hexadecimal numbering systems. Define binary, decimal, octal, and hexadecimal numbering systems. Explain how binary code is used with computers. Explain how binary code is used with computers. Convert binary numbers into decimal numbers. Convert binary numbers into decimal numbers.

3. What is binary to computers?

4. The binary number system is a simple, yet effective method of representing data to computers. Using a numeric code, the binary number system enables computers to understand and interpret all data as simple number combinations. The binary number system is a simple, yet effective method of representing data to computers. Using a numeric code, the binary number system enables computers to understand and interpret all data as simple number combinations.

5. Binary: The binary number system is a base 2 number system, meaning that it relies on only two numbers. The binary number system is a base 2 number system, meaning that it relies on only two numbers.

6. How does a computer see Data?

7. In an electronic circuit there are only two possible states: either the circuit can be turned on, or it can be turned off. So, binary numbers - either a 1 or a 0 - work perfectly. In an electronic circuit there are only two possible states: either the circuit can be turned on, or it can be turned off. So, binary numbers - either a 1 or a 0 - work perfectly.

8. How does a computer know the alphabet from A - Z

9. ASCII code was created to match patterns of 1s and 0s with characters so that computers can "understand" and record the various characters that users input with a keyboard. ASCII code was created to match patterns of 1s and 0s with characters so that computers can "understand" and record the various characters that users input with a keyboard.

10. ASCII CODE Acronym for the American Standard Code for Information Interchange. Pronounced ask-ee, ASCII is a code for representing English characters as numbers, with each letter assigned a number from 0 to 127 in binary form. Acronym for the American Standard Code for Information Interchange. Pronounced ask-ee, ASCII is a code for representing English characters as numbers, with each letter assigned a number from 0 to 127 in binary form.

11. Note: Every binary code "1" means electricity is on. Every binary code "0" means electricity is off. Sending sequences of 1s and 0s to a computer opens and closes computer circuits. Every binary code "1" means electricity is on. Every binary code "0" means electricity is off. Sending sequences of 1s and 0s to a computer opens and closes computer circuits. Translating from keystroke, to binary, to onscreen letter occurs in a nanosecond—one billionth of a second. Translating from keystroke, to binary, to onscreen letter occurs in a nanosecond—one billionth of a second.

12. Bits and Bytes Data entered into a computer is translated into binary number code and transported electronically to the CPU. A single digit of binary code, such as a 0 or 1, is called a bit. Eight bits strung together are called a byte. Data entered into a computer is translated into binary number code and transported electronically to the CPU. A single digit of binary code, such as a 0 or 1, is called a bit. Eight bits strung together are called a byte.

13. Number System Binary01 Binary01 Octal01234567 Octal01234567 Decimal0123456789 Decimal0123456789 Hex0123456789ABCDEF Hex0123456789ABCDEF

14. Lots of Bytes Eight Bits1 Byte Eight Bits1 Byte Kilobyte1,024 Bytes Kilobyte1,024 Bytes Megabyte1,048,576 bytes Megabyte1,048,576 bytes Gigabyte 1,073,741,824 Bytes Gigabyte 1,073,741,824 Bytes Terabyte 1,099,511,627,776 Bytes Terabyte 1,099,511,627,776 Bytes

15. Counting in Number Systems How many numbers can be presented using your fingers? How many numbers can be presented using your fingers?

16. Counting in Number Systems Your 10 fingers can now represent a value up to 1023 with each position representing a power of 2 Your 10 fingers can now represent a value up to 1023 with each position representing a power of 2

17. Decimal Values of Binary Digit Positions Binary positon Binary positon 10 9 8 7 6 5 4 3 2 1 Power of 2 Value Power of 2 Value 2 9 2 8 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 Decimal Value Decimal Value 512+256+128+64+32+ 16+ 8+ 4+ 2+ 1 Answer = 1023

18. Homework Work sheet Students may start in class. Students may start in class. Student may access all homework and class work assignments @ www.nylearns.org/hcordero Student may access all homework and class work assignments @ www.nylearns.org/hcordero