Systems (Two's Complement and Binary PPQ's)

Question 1

Convert the number −120 into 8 bit two’s complement.
1 mark

2018 question 1

Answer 1

1000 1000

From SQA marking scheme

Question 2

Convert the following 8-bit two’s complement number into denary.
1001 1010
1 mark

2019 question 1

Answer 2

-102

From SQA marking scheme

Question 3

Two’s complement can be used to represent positive and negative integers.
State the range of denary values that can be represented using 32‐bit two’s
complement.
2 marks

2022 question 1

Answer 3

• -2^31 OR -2 147 483 648
• 2^31 – 1 OR 2 147 483 647

Help me out guys!

From SQA marking scheme

Question 4

Write the following binary number using floating‐point representation. −111 0000 1111.0101
There are 16 bits for the mantissa (including the sign bit) and 8 bits for the exponent.

Sign:
Mantissa:
Exponent:

2022 question 2

Answer 4

• sign bit: 1
• 111 0000 1111 0101
• exponent: 0000 1011

From SQA marking scheme

Question 5

Convert the 8-bit two’s complement number 1111 0000 into denary.
1 mark

2023 question 1

Answer 5

-16

From SQA marking scheme

Question 6

Convert the binary number below into floating-point representation. −0.0000 0101 0000 1111
There are 16 bits for the mantissa (including the sign bit) and 8 bits for the exponent.
3 marks

2023 question 3(a)

Answer 6

• Sign: 1
• Remaining mantissa:
  101 0000 1111 0000
• Exponent: 1111 1011

From SQA marking scheme

Question 7

State the effect of increasing the number of bits allocated to the mantissa.
1 mark

2023 question 3(b)

Answer 7

Floating point numbers could be stored more precisely/accurately.

From SQA marking scheme