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3 questions · 5 marks
Binary, denary and hexadecimal patterns represent numbers.
Convert the binary pattern 1110 1100 to denary.
Award one mark for:
236
Why: Correct: 128 + 64 + 32 + 8 + 4 = 236 (1).
55
Why: Reads the place values from the wrong end (the left-hand bit as 1), so the value is wrong.
5
Why: Counts the 1s instead of adding their place values.
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.
Binary, denary and hexadecimal patterns represent numbers.
Convert the hexadecimal number 82 to 8-bit binary.
Award one mark for each correct nibble in the correct order:
0 marks if the response is not 8-bit binary.
1000 0010
Why: Each digit is 4 bits: 8 = 1000, 2 = 0010 (2).
1000 0011
Why: Converts 2 as if it were the next digit up. The first nibble is correct (1); the second is not.
0010 1000
Why: The nibbles are in the wrong order. Neither nibble is correct.
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