87
1111 degrees 1111 degrees 1111 degrees
Each hexadecimal digit (or nybble) is the equivalent of 4 binary digits (or bits) with a decimal value of 0-15. Convert each nybble into (4) binary (digits) and string them together, remembering the conversion of decimal 0-15 to binary: Hex -> Dec -> Binary 0 -> 00 -> 0000 1 -> 01 -> 0001 2 -> 02 -> 0010 3 -> 03 -> 0011 4 -> 04 -> 0100 5 -> 05 -> 0101 6 -> 06 -> 0110 7 -> 07 -> 0111 8 -> 08 -> 1000 9 -> 09 -> 1001 A -> 10 -> 1010 B -> 11 -> 1011 C -> 12 -> 1100 D -> 13 -> 1101 E -> 14 -> 1110 F -> 15 -> 1111 So to convert 0x6AF to binary: 6 -> 0110 A -> 1010 F -> 1111 => 0x6AF = 0110 1010 1111 = 011010101111 (without the spaces showing the hex nybbles)
542AM the next day
1111
1010 base 2 = 10 base 10 1010 base 10 = 11 1111 0010 base 2
87
detects the invalid portion of the bcd number codes (1010-1111)
101, 202, 303, 404, 505, 606, 707, 808, 909, 1010, 1111, . . .
It is 5 hours:9-1010-1111-1212-11-2
The 1's complement is formed by inverting every binary digit (bit) of the number - if it is a 0 it becomes a 1, otherwise it is a 1 and becomes a 0. If 10 is in base 2, then its 1's compliment is 01 or just 1. If 10 is in base 10, then in binary it is 1010 and its 1's complement is 0101 = 5 in decimal. However, if more bits are being used to store it, there would be leading 0s that get inverted to 1s and so the resultant number is different; examples: 8 bits (a byte): decimal 10 = 0000 1010 → 1111 0101 = 245 in decimal 16 bits: decimal 10 = 0000 0000 0000 1010 → 1111 1111 1111 0101 = 65525 Next, if 2s complement is being used to represent negative numbers, the binary 1111 0101 represents decimal -11; similarly 1111 1111 1111 0101 represents decimal -11.
101
101, 202, 303, 404, 505, 606, 707, 808, 909, 1010, 1111, 1212
The answer is 1 0101 0111 1110 1011 1011 0011 1111 1010 0001 0111
They are, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111.
1 + 1,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111 = 1,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,111,112 Unless it is binary, in which case: 1 + 111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 1111 11111 1111 1111 1111 1111 = 1000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000 0000
10 = 1010, 11 = 1011, 12 = 1100, 13 = 1101, 14 = 1110, 15 = 1111, 16 = 10000.