6 Edexcel GCSE Computer Science (1CP2) exam-style questions on Denary to Hexadecimal Conversion (2.1 Binary), 9 marks in all. Answer them on paper or print them, then open the mark schemes and example answers to see how each is marked.
Computer systems manipulate bit patterns.
Convert the hexadecimal number D5 to denary.
Award one mark for:
213
Why: 13 × 16 + 5 = 213 (1).
93
Why: Takes the right-hand digit as the 16s, so the value is wrong.
18
Why: Adds the two digits instead of multiplying the first by 16.
Computer systems manipulate bit patterns.
Convert the hexadecimal number F4 to denary.
Award one mark for:
244
Why: 15 × 16 + 4 = 244 (1).
79
Why: Takes the right-hand digit as the 16s, so the value is wrong.
19
Why: Adds the two digits instead of multiplying the first by 16.
Computer systems manipulate bit patterns.
Convert the hexadecimal number 8F to denary.
Award one mark for:
143
Why: 8 × 16 + 15 = 143 (1).
248
Why: Takes the right-hand digit as the 16s, so the value is wrong.
23
Why: Adds the two digits instead of multiplying the first by 16.
Computers manipulate binary patterns.
Convert the denary number 90 to hexadecimal.
Award one mark for each correct digit in the correct position:
Answer: 5A
5A
Why: 90 ÷ 16 = 5 remainder 10, so the digits are 5 and A: both digits are correct (2).
510
Why: One digit is correct (1), but a digit over 9 is written in denary instead of as a letter.
A5
Why: The digits are the wrong way round, so neither is in the correct position.
Computers manipulate binary patterns.
Convert the denary number 161 to hexadecimal.
Award one mark for each correct digit in the correct position:
Answer: A1
A1
Why: 161 ÷ 16 = 10 remainder 1, so the digits are A and 1: both digits are correct (2).
101
Why: One digit is correct (1), but a digit over 9 is written in denary instead of as a letter.
1A
Why: The digits are the wrong way round, so neither is in the correct position.
Computer systems manipulate bit patterns.
Convert the denary number 244 to hexadecimal.
Award one mark for each correct digit in the correct position:
Answer: F4
F4
Why: 244 ÷ 16 = 15 remainder 4, so the digits are F and 4: both digits are correct (2).
154
Why: One digit is correct (1), but a digit over 9 is written in denary instead of as a letter.
4F
Why: The digits are the wrong way round, so neither is in the correct position.
Teachers: print these as a worksheet with the mark schemes at the end, and sign your school up to set your classes activities on Denary to Hexadecimal Conversion.
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