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3 questions · 5 marks
Computers manipulate binary patterns.
Convert the binary pattern 1010 0100 to denary.
Award one mark for:
164
Why: Correct: 128 + 32 + 4 = 164 (1).
37
Why: Reads the place values from the wrong end (the left-hand bit as 1), so the value is wrong.
3
Why: Counts the 1s instead of adding their place values.
Binary patterns can represent numbers.
Convert the hexadecimal number D3 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.
1101 0011
Why: Each digit is 4 bits: D = 1101, 3 = 0011 (2).
1101 0100
Why: Converts 3 as if it were the next digit up. The first nibble is correct (1); the second is not.
0011 1101
Why: The nibbles are in the wrong order. Neither nibble is correct.
Computers manipulate binary patterns.
Complete the table to show the result of the 8-bit binary addition.
| 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1 |
|---|---|---|---|---|---|---|---|
| 1 | 0 | 0 | 1 | 0 | 1 | 0 | 1 |
| 0 | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
Award one mark for each correct nibble in the correct order:
0 marks if the response is not 8-bit binary.
1110 0100
Why: 149 + 79 = 228, carrying where a column adds to 2: both nibbles are correct (2).
1110 0101
Why: A slip in the last bit. The first nibble is correct (1); the second is not.
1101 1111
Why: Writes 1 in every column with a 1 and never carries. Neither nibble is correct.
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