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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 693 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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3 questions · 7 marks

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1Convert2 marksBinary to Hexadecimal Conversion Swap Remove

Binary, denary and hexadecimal patterns represent numbers.

Convert the binary pattern 1100 1010 to hexadecimal.

[2 marks]
Mark scheme

Award one mark for each correct digit in the correct position:

  • C (1)
  • A (1)

Answer: CA

Example answers and how they were marked
Full marks2/2

CA

Why: Each nibble is one hexadecimal digit: 1100 = C, 1010 = A: both digits are correct (2).

Some marks1/2

C10

Why: One digit is correct (1), but the second is written as 10 in denary instead of A.

No marks0/2

AC

Why: The digits are the wrong way round, so neither is in the correct position.

2Convert2 marksDenary to Hexadecimal Conversion Swap Remove

Computers manipulate binary patterns.

Convert the denary number 90 to hexadecimal.

[2 marks]
Mark scheme

Award one mark for each correct digit in the correct position:

  • 5 (1)
  • A (1)

Answer: 5A

Example answers and how they were marked
Full marks2/2

5A

Why: 90 ÷ 16 = 5 remainder 10, so the digits are 5 and A: both digits are correct (2).

Some marks1/2

510

Why: One digit is correct (1), but a digit over 9 is written in denary instead of as a letter.

No marks0/2

A5

Why: The digits are the wrong way round, so neither is in the correct position.

3Calculate3 marksAdding Binary Numbers Swap Remove

Computers manipulate binary patterns.

(a)

Complete the table to show the 8-bit result of the binary addition.

[2 marks]
1286432168421
10111001
10111100
Mark scheme

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

  • 0111 (1)
  • 0101 (1)

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

Ignore a carry shown beyond the eighth bit.

Example answers and how they were marked
Full marks2/2

0111 0101

Why: 185 + 188 = 373, which needs 9 bits; the 8 bits that are kept are both correct (2).

Some marks1/2

0000 0101

Why: Forgets to carry the 1s. The second nibble is correct (1); the first is not.

No marks0/2

1011 1101

Why: Never carries. Neither nibble is correct.

(b)

State the name of the error that occurs when this addition is carried out.

[1 mark]
Mark scheme

Award one mark for:

  • overflow (error) (1)
Example answers and how they were marked
Full marks1/1

Overflow

Why: The result needs more bits than are available (1).

No marks0/1

Underflow

Why: A near miss: the result is too big for 8 bits, not too small.

No marks0/1

A syntax error

Why: A syntax error is a mistake in a program's code, not in arithmetic.

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