O-LevelComputer ScienceData Representation2210/12 · May/June 2024 · Q311 Marks
Binary is a base 2 number system.
- (a)Give the name of the number system that is base 16.[1]
- (b)(i)Three denary numbers are entered into a computer. The computer converts the numbers and stores them as binary. Give the binary number that would be stored for each of the denary numbers. 10 50 201 Working space[3]
- (b)(ii)Explain why the data is converted to binary by the computer.[2]
- (c)The two binary integers 00110000 and 01100110 are added together. Add the binary integers using binary addition and show your answer in binary. Show all your working.[3]
- (d)The denary integer -32 is stored as a two's complement integer. Calculate the two's complement integer that would be stored. Show all your working.[2]
Mark scheme
Marking points from the official mark scheme (May/June 2024). The mark or mark type is shown in brackets.
- [1] Hexadecimal
- [3] 1010 110010 11001001
- [2] Two from: • Computers use logic gates/switches ... • ... that only process the values 1 and 0 // that only have two states
- [3] One mark for evidence of working, for example 2 carries One mark for each correct nibble (Max 2) 11 0011 0000 0110 0110 1001 0110
- [2] One marking for evidence of working For example, flip and add One mark for correct binary 11100000
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