Number System – Class 03

What is a number with a plus (+) or minus (-) sign before it called?
(a) Signed number (b) Real number (c) Complex number (d) Imaginary number
Answer: a
What is the leftmost bit called that indicates a positive or negative number in computers?
(a) Carry bit (b) Sign bit (c) Zone bit (d) Data bit
Answer: b
What kind of number is it if the sign bit is '0'?
(a) Positive (b) Negative (c) Undefined (d) Zero
Answer: a
What does it indicate if the sign bit is '1'?
(a) Positive (b) Negative (c) Infinite (d) Unreal
Answer: b
What are the remaining bits to the right of the sign bit called?
(a) Magnitude bits (b) Carry bits (c) Zone bits (d) Parity bits
Answer: a
Generally, how many bits register is used in computers?
(a) 5-bit (b) 8-bit (c) 9-bit (d) 15-bit
Answer: b
How many methods are there to represent negative numbers in digital systems?
(a) 2 (b) 3 (c) 4 (d) 5
Answer: b
What is the position of the sign bit in an 8-bit register?
(a) 1st (b) 4th (c) 7th (d) 8th
Answer: d
How many bits are there for magnitude in an 8-bit register?
(a) 7 (b) 8 (c) 1 (d) 4
Answer: a
Which is the 8-bit form of $-5$ in Sign & Magnitude representation?
(a) 00000101 (b) 10000101 (c) 11111010 (d) 11111011
Answer: b

What is the process of inverting the bits of a binary number called?
(a) 1's complement (b) 2's complement (c) Real value (d) Encoding
Answer: a
What replaces 0 in 1's complement representation?
(a) 0 (b) 1 (c) 2 (d) Sign
Answer: b
What replaces 1 in 1's complement representation?
(a) 0 (b) 1 (c) Plus (d) Minus
Answer: a
Which is the 1's complement value of binary 1010?
(a) 0101 (b) 1011 (c) 1100 (d) 0000
Answer: a
What is the 1's complement of $+7$ (00000111) in an 8-bit register?
(a) 11111000 (b) 10000111 (c) 11111001 (d) 00001000
Answer: a
Which is the 1's complement of the binary number 0000?
(a) 1111 (b) 0000 (c) 1000 (d) 0101
Answer: a
Which value represents $-0$ (Minus Zero) in 1's complement system?
(a) 00000000 (b) 11111111 (c) 10000000 (d) None
Answer: b
What is obtained by re-inverting the 1's complement of a number?
(a) Original number (b) 2's complement (c) 9's complement (d) Negative number
Answer: a
What does the number 11111110 represent in 1's complement in an 8-bit register?
(a) $-1$ (b) $+1$ (c) $-2$ (d) $+2$
Answer: a
1's complement is primarily the function of which gate?
(a) AND (b) OR (c) NOT (d) XOR
Answer: c

What is obtained by adding 1 to the 1's complement?
(a) 2's complement (b) Real value (c) Carry bit (d) New number
Answer: a
Which method is used to represent negative numbers in modern computers?
(a) Real value (b) 1's complement (c) 2's complement (d) BCD code
Answer: c
Which method eliminates the complexity of plus zero and minus zero?
(a) Real value (b) 1's complement (c) 2's complement (d) All of them
Answer: c
Which is the 2's complement value of $-1$ in an 8-bit register?
(a) 11111111 (b) 10000001 (c) 11111110 (d) 00000001
Answer: a
What is the 2's complement value of binary 1010?
(a) 0101 (b) 0110 (c) 1100 (d) 0001
Answer: b
What is the 2's complement (i.e., -5) of $+5$ (00000101) in an 8-bit register?
(a) 11111010 (b) 11111011 (c) 10000101 (d) 11111100
Answer: b
What happens if you take the 2's complement of a 2's complemented number?
(a) Original number (b) 1's complement (c) Value doubles (d) Becomes zero
Answer: a
What is the number range in an 8-bit 2's complement structure?
(a) -127 to +127 (b) -128 to +127 (c) 0 to 255 (d) -128 to +128
Answer: b
What is the main advantage of 2's complement representation?
(a) Simplifies circuits (b) Faster calculation (c) Less memory (d) Both a & b
Answer: d
What does the number 10000000 represent in 2's complement in an 8-bit register?
(a) $-128$ (b) $+128$ (c) $-0$ (d) $-1$
Answer: a

How is subtraction performed in the 2's complement system?
(a) Direct subtraction (b) Through addition (c) Through multiplication (d) Through division
Answer: b
If a 9th bit is generated in 2's complement addition, what is it called?
(a) Sign bit (b) Carry bit (c) Zone bit (d) Parity bit
Answer: b
What rule applies to the carry bit in 2's complement arithmetic operations?
(a) Discarded (b) Added (c) Subtracted (d) Becomes sign bit
Answer: a
If the sum in an 8-bit register is (1) 00000101, what is the actual answer?
(a) 5 (b) 257 (c) -5 (d) 9
Answer: a
What will be the 2's complement sum of $+12$ and $-5$ ?
(a) $+7$ (b) $-7$ (c) $+17$ (d) $-17$
Answer: a
If the sign bit is '1' in a 2's complement addition, how is the result stored?
(a) Positive (b) In complemented form (c) Incorrect value (d) Zero
Answer: b
What will be the sign bit when two negative numbers are added in 2's complement?
(a) 0 (b) 1 (c) Carry bit (d) Zero
Answer: b
Which part of the computer performs complement addition?
(a) Adder (b) Encoder (c) Decoder (d) Register
Answer: a
Which is the normal sum of $+5$ and $+3$ in an 8-bit register?
(a) 00001000 (b) 11111000 (c) 00000111 (d) 10001000
Answer: a
What is it called in 2's complement when a result exceeds the register capacity?
(a) Overflow (b) Underflow (c) Carry (d) Error
Answer: a