Lesson Notes By Weeks and Term - Junior Secondary School 2

SUBJECT: ICT

CLASS:� JSS 2

DATE:

TERM: 1st TERM

�

�
WEEK 8

TOPIC: NUMBER BASE

Number base is divided into five categories. These are:

1. Decimal�

2. Binary�

3. Octal�

4. Hexadecimal�

1. Decimal Numeral System - Base-10 .Decimal numbers uses digits from 0 to 9

These are the regular numbers that we use.

Example:

253810 = 2�103+5�102+3�101+8�100 = 2000+ 500+ 30 +8= 2538

1. Binary Numeral System - Base-2. Binary numbers uses only 0 and 1 digits.

Examples:

101012 = 10101 = 1�24+0�23+1�22+0�21+1�20 = 16+4+1= 21

101112 = 10111 = 1�24+0�23+1�22+1�21+1�20 = 16+4+2+1=23

1000112 = 100011 = 1�25+0�24+0�23+0�22+1�21+1�20 =32+21= 35

1. Octal Numeral System - Base-8 .Octal numbers uses digits from 0 to 7.

Examples:

278 = 2�81+7�80 = 16+7 = 23

308 = 3�81+0�80 = 24

43078 = 4�83+3�82+0�81+7�80= 2247

1. Hexadecimal Numeral System - Base-16 .Hex numbers uses digits from 0,1,2,3,4,5,6,7,8, 9 ,A,B,C,D,E,F

Examples:

2816 = 28 = 2�161+8�160 = 40

2F16 = 2FH = 2�161+15�160 = 47

BC1216 = BC12H = 11�163+12�162+1�161+2�160= 48146

�