Summary GCSE AQA Computer Science - Useful guides

Binary to denary

128 64 32 16 8 4 2 1




Den Hex Bin
0 0 0000
1 1 0001
2 2 0010
3 3 0011
4 4 0100
5 5 0101
6 6 0110
7 7 0111
8 8 1000
9 9 1001
10 A 1010
11 B 1011
12 C 1100
13 D 1101
14 E 1110
15 F 1111


Bits Combinations Max num
1 2 1
2 4 3
3 8 7
4 16 15
5 32 31
6 64 63
7 128 127
8 256 255


0 + 0 = 0
1 + 0 = 1
0 + 1 = 1
1 + 1 = 10
1+1 + 1 = 11