Step-1: MVI A, 42H given 42 value in hexadecimal and storing value in Accumulator A.

For solving problem, convert (42) 16 into decimal is (66) 10

Step-2: MVI B, 05H given 05 value in hexadecimal and storing value in Accumulator B.

For solving problem, convert (05) 16 into decimal is (05) 10

Step-3: ADD B until UGC will fail. Contents of accumulator A value and B value will add.

66+5=71

Step-4: DCR B it means decrement by 1.

71+4=75

Step-5: JNZ means jump not equals to zero.

75+3=78

78+2=80

80+1=81

Step-6: It became false, then execute next statement.

ADI 25H means add 25H to (81) 10

(25) 16 = (37) 10

37+81=(118) 10

Finally

convert decimal value into Hexadecimal.

(118) 10 = (76) 16

Step-7: HLT means halt the program.

Note: We are converting hexadecimal into decimal for only calculation. without conversion also we can solve a problem.

For solving problem, convert (42) 16 into decimal is (66) 10

Step-2: MVI B, 05H given 05 value in hexadecimal and storing value in Accumulator B.

For solving problem, convert (05) 16 into decimal is (05) 10

Step-3: ADD B until UGC will fail. Contents of accumulator A value and B value will add.

66+5=71

Step-4: DCR B it means decrement by 1.

71+4=75

Step-5: JNZ means jump not equals to zero.

75+3=78

78+2=80

80+1=81

Step-6: It became false, then execute next statement.

ADI 25H means add 25H to (81) 10

(25) 16 = (37) 10

37+81=(118) 10

Finally

convert decimal value into Hexadecimal.

(118) 10 = (76) 16

Step-7: HLT means halt the program.

Note: We are converting hexadecimal into decimal for only calculation. without conversion also we can solve a problem.