1. Computer Studies Today Chapter 19 1 Chapter 19

2. Computer Studies Today Chapter 19 2 »Information stored in a computer is in two states: –ON –OFF

3. Computer Studies Today Chapter 19 3 »They are represented by the binary digits ‘1’ and ‘0’ respectively. »As the number of bits increases, the bit pattern is increased and more information can be stored.

4. Computer Studies Today Chapter 19 4

5. 5 »Numbers can be represented in different number systems: –Denary number system –Binary number system

6. Computer Studies Today Chapter 19 6 –Octal number system –Hexadecimal number system

7. Computer Studies Today Chapter 19 7 »Digits 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 are used to represent numbers. »It is a base-10 number system. »A number is formed by the combination of the digits, for example 21 10, 103 10, 0.3 10.

8. Computer Studies Today Chapter 19 8 Denary Numbers in Expanded Form The denary number 4192 10 in expanded form is:

9. Computer Studies Today Chapter 19 9 i.e. 4192 10 = 4  10 3 + 1  10 2 + 9  10 1 + 2  10 0

10. Computer Studies Today Chapter 19 10 The decimal fraction 0.213 10 in expanded form is:

11. Computer Studies Today Chapter 19 11 i.e. 0.213 10 = 2  10 –1 + 1  10 –2 + 3  10 –3

12. Computer Studies Today Chapter 19 12 »Digits 0 and 1 are used to represent numbers. »It is a base-2 number system. »A number is formed by the combination of the digits, for example 10 2, 110 2, 0.01 2.

13. Computer Studies Today Chapter 19 13 Binary Numbers in Expanded Form The binary number 1111 2 in expanded form is:

14. Computer Studies Today Chapter 19 14 i.e. 1111 2 = 1  2 3 + 1  2 2 + 1  2 1 + 1  2 0

15. Computer Studies Today Chapter 19 15 The binary fraction 0.1011 2 in expanded form is:

16. Computer Studies Today Chapter 19 16 i.e. 0.1011 2 = 1  2 –1 + 0  2 –2 + 1  2 –3 + 1  2 –4

17. Computer Studies Today Chapter 19 17 »Digits 0, 1, 2, 3, 4, 5, 6 and 7 are used to represent numbers. »It is a base-8 number system. »A number is formed by the combination of the digits, for example 123 8, 470 8, 5431 8.

18. Computer Studies Today Chapter 19 18 Octal Numbers in Expanded Form The octal number 357 8 in expanded form is:

19. Computer Studies Today Chapter 19 19 i.e. 357 8 = 3  8 2 + 5  8 1 + 7  8 0

20. Computer Studies Today Chapter 19 20 »Digits 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and letters A, B, C, D, E, F are used to represent numbers. »It is a base-16 number system.

21. Computer Studies Today Chapter 19 21 »A number is formed by the combination of the digits and the letters, for example 2C4D 16, A95 16.

22. Computer Studies Today Chapter 19 22 Hexadecimal Numbers in Expanded Form The hexadecimal number 2C3D 16 in expanded form is:

23. Computer Studies Today Chapter 19 23 i.e. 2C3D 16 = 2  16 3 + 12  16 2 + 3  16 1 + 13  16 0