Page 28 - TP_iPlus_V2.1_Class7
P. 28
For example, let us subtract the binary number (111) from (1000) .
2 2
X Y X – Y
1 1
0 0 0 – 0 = 0 _____
0 (10) (10) (10) Borrow
0 – 1 = 1
0 1
(borrow 1, so that 10 – 1 = 1) 1 0 0 0
1 0 1 – 0 = 1 – 1 1 1
1 1 1 – 1 = 0 0 0 0 1
To Sum Up
The smallest piece of data that can be recognised and used by the computer is known
as a bit or a binary digit.
A number system is a way to express quantities used for counting, comparing amounts,
performing calculations and representing values.
A number system made up of ten symbols, 0 to 9, is known as the decimal number
system.
A number system made up of only two symbols, 0 and 1, is known as the binary
number system.
A number system made up of eight symbols, 0 to 7, is known as the octal number
system.
A number system made up of sixteen symbols, 0 to 9 and A to F, is known as the
hexadecimal number system.
Exercise
Section A (Objective)
A. Tick (3) the correct option.
1. Which of the following is not the correct name for the number 0?
a. Nought b. Naught
c. Zilch d. Unity
2. A single binary digit is called a ................................ .
a. Byte b. Bit
c. Word d. All of these
26
iPlus (Ver. 2.1)-VII

