# Digital Arithmetic Operations and Circuits MCQ Questions & Answers

Digital Arithmetic Operations and Circuits MCQs : This section focuses on the "Digital Arithmetic Operations and Circuits". These Multiple Choice Questions (MCQs) should be practiced to improve the Digital Arithmetic Operations and Circuits skills required for various interviews (campus interview, walk-in interview, company interview), placement, entrance exam and other competitive examinations.

Question 1

The selector inputs to an arithmetic/logic unit (ALU) determine the:

A. selection of the IC
B. arithmetic or logic function
C. data word selection
D. clock frequency to be used

Question 2

C. requires the carry-out of the less significant adder to be connected to the carry-in of the next significant adder.
D. requires 4 adders and the connection of the carry out of the less significant adder to the carry-in of the next significant adder.

Question 3

A. TRUE
B. FALSE

Question 4

One way to make a four-bit adder perform subtraction is by:

A. inverting the output.
B. inverting the carry-in.
C. inverting the B inputs.
D. grounding the B inputs.

Question 5

A. It is slower than the ripple-carry adder.
B. It is easier to implement logically than a full adder.
C. It is faster than a ripple-carry adder.

Question 6

The most commonly used system for representing signed binary numbers is the:

A. 2's-complement system.
B. 1's-complement system.
C. 10's-complement system.
D. sign-magnitude system.

Question 7

When performing subtraction by addition in the 2's-complement system:

A. the minuend and the subtrahend are both changed to the 2's-complement.
B. the minuend is changed to 2's-complement and the subtrahend is left in its original form.
C. the minuend is left in its original form and the subtrahend is changed to its 2's-complement.
D. the minuend and subtrahend are both left in their original form.

Question 8

Multiply the following binary numbers. 1010   1011   1001 ×0011   ×0111   ×1010

A. 0001  1110    0100  1101    0101  1011
B. 0001  1110    0100  1100    0101  1010
C. 0001  1110    0100  1101    0101  1010
D. 0001  1101    0100  1101    0101  1010

Question 9

Which of the following is correct for full adders?

C. Full adders are limited to two inputs since there are only two binary digits.
D. In a parallel full adder, the first stage may be a half adder.

Question 10

When multiplying 13 × 11 in binary, what is the third partial product?

A. 1011
B. 0
C. 100000
D. 100001

Question 11

An 8-bit register may provide storage for two's-complement codes within which decimal range?

A. +128 to –128
B. –128 to +127
C. +128 to –127
D. +127 to –127

Question 12

Convert each of the following signed binary numbers (two's-complement) to a signed decimal number.00000101        11111100        11111000

A. –5    +4    +8
B. +5    –4    –8
C. –5    +252    +248
D. +5    –252    –248

Question 13

What is the first thing you will need if you are going to use a macrofunction?

A. A complicated design project
B. An experienced design engineer
C. Good documentation
D. Experience in HDL

Question 14

Subtract the following hexadecimal numbers. 47   34   FA –25   –1C   –2F

A. 22    18    CB
B. 22    17    CB
C. 22    19    CB
D. 22    18    CC

Question 15

For a 4-bit parallel adder, if the carry-in is connected to a logical HIGH, the result is:

A. the same as if the carry-in is tied LOW since the least significant carry-in is ignored.
B. that carry-out will always be HIGH.
C. a one will be added to the final result.
D. the carry-out is ignored.

Question 16

What is the most important operation in binary-coded decimal (BCD) arithmetic?

B. subtraction
C. multiplication
D. division

Question 17

Subtract the following binary numbers. 0101 1000   1010 0011   1101 1110 –0010 0011   –0011 1000   –0101 0111

A. 0011  0100    0110  1010    1000  0110
B. 0011  0101    0110  1011    1000  0111
C. 0011  0101    0110  1010    1000  0111
D. 0011  0101    0110  1010    1000  0110

Question 18

The 2's-complement system is to be used to add the signed binary numbers 11110010 and 11110011. Determine, in decimal, the sign and value of each number and their sum.

A. –113 and –114, –227
B. –14 and –13, –27
C. –11 and –16, –27
D. –27 and –13, –40

Question 19

A. 60    3C    116
B. 62    3C    118
C. 61    3C    117
D. 61    3D    117

Question 20

Could the sum output of a full-adder be used as a two-bit parity generator?

A. Yes
B. No

Question 21

Which of the following is the primary advantage of using binary-coded decimal (BCD) instead of straight binary coding?

A. Fewer bits are required to represent a decimal number with the BCD code.
B. BCD codes are easily converted from decimal.
C. the relative ease of converting to and from decimal
D. BCD codes are easily converted to straight binary codes.

Question 22

Why is a fast-look-ahead carry circuit used in the 7483 4-bit full-adder?

A. to decrease the cost
B. to make it smaller
C. to slow down the circuit
D. to speed up the circuit

Question 23

How many BCD adders would be required to add the numbers 97310 + 3910?

A. 3
B. 4
C. 5
D. 6

Question 24

If [A] = 1011 1010, [B] = 0011 0110, and [C] = [A] • [B], what is [C 4..2] in decimal?

A. 1
B. 2
C. 3
D. 4

Question 25

Add the following BCD numbers. 0110   0111   1001 0101   1000   1000

A. 0000  1011    0000  1111    0001  0001
B. 0001  0001    0001  0101    0001  0001
C. 0000  1011    0000  1111    0001  0111
D. 0001  0001    0001  0101    0001  0111

Question 26

A. determine sign and magnitude
B. reduce propagation delay
C. add a 1 to complemented inputs
D. increase ripple delay

Question 27

If B[7..0] = 10100101, what is the value of B[6..2]?

A. 10100
B. 1001
C. 10010
D. 101

Question 28

An input to the mode pin of an arithmetic/logic unit (ALU) determines if the function will be:

A. one's-complemented
B. arithmetic or logic
C. positive or negative
D. with or without carry

Question 29

The two's-complement system is to be used to add the signed numbers 11110010 and 11110011. Determine, in decimal, the sign and value of each number and their sum.

A. –14 and –13, –27
B. –113 and –114, 227
C. –27 and –13, 40
D. –11 and –16, –27

Question 30

Convert the decimal numbers 275 and 965 to binary-coded decimal (BCD) and add. Select the BCD code groups that reflect the final answer.

A. 1101 1110 1010
B. 1110 1010 1110
C. 0001 0010 0100 0000
D. 0010 0011 0100 0000

Question 31

The range of positive numbers when using an eight-bit two's-complement system is:

A. 0 to 64
B. 0 to 100
C. 0 to 127
D. 0 to 256

Question 32

Perform the following hex subtraction: ACE16 – 99916 =

A. 23516
B. 13516
C. 3516
D. 33516

Question 33

Convert each of the decimal numbers to two's-complement form and perform the addition in binary. +13 –10 add –7 add +15

A. 0001  0100    0000  0101
B. 0000  0110    0001  1001
C. 0000  0110    0000  0101
D. 1111  0110    1111  0101

Question 34

Determine the two's-complement of each binary number.00110        00011        11101

A. 11001    11100    00010
B. 00111    00010    00010
C. 00110    00011    11101
D. 11010    11101    00011

Question 35

Find the 2's complement of –1101102.

A. 1101002
B. 1010102
C. 10012
D. 10102

Question 36

How many inputs must a full-adder have?

A. 2
B. 3
C. 4
D. 5

Question 37

The binary adder circuit is designed to add ________ binary numbers at the same time.

A. 2
B. 4
C. 6
D. 8

Question 38

Solve this binary problem: 01110010 – 01001000 =

A. 11010
B. 101010
C. 1110010
D. 111100

Question 39

When 1100010 is divided by 0101, what is the decimal remainder?

A. 2
B. 3
C. 4
D. 6

Question 40

Convert each of the signed decimal numbers to an 8-bit signed binary number (two's-complement).+7        –3        –12

A. 0000  0111    1111  1101    1111  0100
B. 1000  0111    0111  1101    0111  0100
C. 0000  0111    0000  0011    0000  1100
D. 0000  0111    1000  0011    1000  1100

Question 41

Solve this BCD problem: 0100 + 0110 =

A. 00010000BCD
B. 00010111BCD
C. 00001011BCD
D. 00010011BCD

Question 42

C. Half-adder does not have a carry-out.
D. Full-adder does not have a carry-out.

Question 43

The summing outputs of a half- or full-adder are designated by which Greek symbol?

A. omega
B. theta
C. lambda
D. sigma

Question 44

Solve this binary problem: 01000110 ÷ 00001010 =

A. 111
B. 10011
C. 1001
D. 11

Question 45

A half-adder circuit would normally be used each time a carry input is required in an added circuit.

A. TRUE
B. FALSE

Question 46

A. two single bits and one carry bit
B. two 2-bit binary numbers
C. two 4-bit binary numbers
D. two 2-bit numbers and one carry bit

Question 47

How many inputs must a full-adder have?

A. 4
B. 2
C. 5
D. 3

Question 48

What are the two types of basic adder circuits?

A. sum and carry
C. asynchronous and synchronous
D. one- and two's-complement

Question 49

Solving –11 + (–2) will yield which two's-complement answer?

A. 1110 1101
B. 1111 1001
C. 1111 0011
D. 1110 1001

Question 50

Add the following binary numbers. 0010 0110   0011 1011   0011 1100 +0101 0101   +0001 1110   +0001 1111

A. 0111 1011    0100  0001    0101  1011
B. 0111 1011    0101  1001    0101  1011
C. 0111 0111    0101  1001    0101  1011
D. 0111 0111    0100  0001    0101  1011

Question 51

Adding in binary, a decimal 26 + 27 will produce a sum of:

A. 111010
B. 110110
C. 110101
D. 101011

Question 52

In VHDL, what is a GENERATE statement?

A. The start statement of a program
B. Not used in VHDL or ADHL
C. A way to get the computer to generate a program from a circuit diagram
D. A way to tell the compiler to replicate several components

Question 53

The binary subtraction 0 – 0 =

A. difference = 0borrow = 0
B. difference = 1borrow = 0
C. difference = 1borrow = 1
D. difference = 0borrow = 1

Question 54

The BCD addition of 910 and 710 will give initial code groups of 1001 + 0111. Addition of these groups generates a carry to the next higher position. The correct solution to this problem would be to:

A. ignore the lowest order code group because 0000 is a valid code group and prefix the carry with three zeros
B. add 0110 to both code groups to validate the carry from the lowest order code group
C. disregard the carry and add 0110 to the lowest order code group
D. add 0110 to the lowest order code group because a carry was generated and then prefix the carry with three zeros

Question 55

What logic function is the sum output of a half-adder?

A. AND
B. exclusive-OR
C. exclusive-NOR
D. NAND

Question 56

The carry propagation delay in 4-bit full-adder circuits:

A. is cumulative for each stage and limits the speed at which arithmetic operations are performed
B. is normally not a consideration because the delays are usually in the nanosecond range
C. decreases in direct ratio to the total number of full-adder stages
D. increases in direct ratio to the total number of full-adder stages, but is not a factor in limiting the speed of arithmetic operations

Question 57

Perform subtraction on each of the following binary numbers by taking the two's-complement of the number being subtracted and then adding it to the first number.01001        0110000011        00111

A. 01100    10011
B. 00110    00101
C. 10110    10101
D. 00111    00100

Question 58

The carry propagation delay in full-adder circuits:

A. is normally not a consideration because the delays are usually in the nanosecond range.
B. decreases in a direct ratio to the total number of FA stages.
C. is cumulative for each stage and limits the speed at which arithmetic operations are performed.
D. increases in a direct ratio to the total number of FA stages but is not a factor in limiting the speed of arithmetic operations.

Question 59

Add the following hex numbers: 011016 + 1001016

A. 1012016
B. 1002016
C. 1112016
D. 12016

Question 60

A. The interconnections are more complex.
B. More stages are required to a full adder.
C. It is slow due to propagation time.
D. All of the above.

Question 61

The decimal value for E16 is:

A. 1210
B. 1310
C. 1410
D. 1510

Question 62

What are constants in VHDL code?

A. Fixed numbers represented by a name
B. Fixed variables used in functions
C. Fixed number types
D. Constants do not exist in VHDL code.