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Exam Questions Edexcel GCSE Computer Science (1CP2)

Denary to Binary Conversion Exam Questions

6 Edexcel GCSE Computer Science (1CP2) exam-style questions on Denary to Binary Conversion (2.1 Binary), 12 marks in all. Answer them on paper or print them, then open the mark schemes and example answers to see how each is marked.

Revise Denary to Binary Conversion first

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1Convert2 marks

Binary, denary and hexadecimal patterns represent numbers.

Convert the denary number 59 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 0011 (1)
  • 1011 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

0011 1011

Why: 59 = 32 + 16 + 8 + 2 + 1: both nibbles are correct (2).

Some marks1/2

0011 1100

Why: Converts 60 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

1101 1100

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

2Convert2 marks

Computers manipulate binary patterns.

Convert the denary number 72 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 0100 (1)
  • 1000 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

0100 1000

Why: 72 = 64 + 8: both nibbles are correct (2).

Some marks1/2

0100 1001

Why: Converts 73 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

0001 0010

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

3Convert2 marks

Computer systems manipulate bit patterns.

Convert the denary number 13 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 0000 (1)
  • 1101 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

0000 1101

Why: 13 = 8 + 4 + 1: both nibbles are correct (2).

Some marks1/2

0000 1110

Why: Converts 14 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

1011 0000

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

4Convert2 marks

Binary patterns can represent numbers.

Convert the denary number 199 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1100 (1)
  • 0111 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

1100 0111

Why: 199 = 128 + 64 + 4 + 2 + 1: both nibbles are correct (2).

Some marks1/2

1100 1000

Why: Converts 200 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

1110 0011

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

5Convert2 marks

Computers manipulate binary patterns.

Convert the denary number 184 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1011 (1)
  • 1000 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

1011 1000

Why: 184 = 128 + 32 + 16 + 8: both nibbles are correct (2).

Some marks1/2

1011 1001

Why: Converts 185 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

0001 1101

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

6Convert2 marks

Computer systems manipulate bit patterns.

Convert the denary number 140 to 8-bit binary.

[2 marks]
Mark scheme

Award one mark for each correct nibble in the correct order:

  • 1000 (1)
  • 1100 (1)

0 marks if the response is not 8-bit binary.

Example answers and how they were marked
Full marks2/2

1000 1100

Why: 140 = 128 + 8 + 4: both nibbles are correct (2).

Some marks1/2

1000 1101

Why: Converts 141 instead (a slip in adding up the place values). The first nibble is correct (1); the second is not.

No marks0/2

0011 0001

Why: The bits are written in reverse, smallest place value first. Neither nibble is correct.

Keep practising Denary to Binary Conversion

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More exam questions on 2.1 Binary

Adding Binary Numbers 6 questions Binary and Hexadecimal Basics 10 questions Binary Shifts 6 questions Binary to Denary Conversion 6 questions Binary to Hexadecimal Conversion 6 questions Denary to Hexadecimal Conversion 6 questions Denary to Negative Binary Conversion 6 questions Hexadecimal to Binary Conversion 6 questions

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