Build a practice paper from 659 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.
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, denary and hexadecimal patterns represent numbers.
Convert the denary number -46 to 8-bit binary using two's complement.
Award one mark for each correct nibble in the correct order:
0 marks if the response is not 8-bit binary.
1101 0010
Why: 46 is 00101110; flip the bits (11010001) and add 1: both nibbles are correct (2).
1101 0001
Why: Flips the bits of 46 but doesn't add 1. The first nibble is correct (1); the second is not.
1010 1110
Why: Uses sign and magnitude (a 1 in front of 46) instead of two's complement. Neither nibble is correct.
Binary patterns can represent numbers.
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 | 1 | 0 |
| 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 |
Award one mark for each correct nibble in the correct order:
0 marks if the response is not 8-bit binary.
1111 0010
Why: 150 + 92 = 242, carrying where a column adds to 2: both nibbles are correct (2).
1111 0011
Why: A slip in the last bit. The first nibble is correct (1); the second is not.
1101 1110
Why: Writes 1 in every column with a 1 and never carries. Neither nibble is correct.
Teachers: build a paper, print it with the mark schemes at the end, and sign your school up to set your classes activities on every topic.
Fetch Decode Explain isn't affiliated with or endorsed by Pearson Edexcel.