normalization - Why can't a negative normalized floating point binary number start with 11? -

studying level computing repeatedly told negative normalised floating point binary number not normalised if starts 11 textbooks, exam questions , teachers.

in case of minus 11 in twos compliment can written 10101 , number in normalised form 10101 00100 follows rule of no 11 @ beginning of number

but minus 1 twos compliment version 11111 , normalised version be, 11111 00100 works breaks rule, 011111 00101 makes number positive , uses many bits, 10111 00100 makes minus 9 instead of minus 1

basically why can't number begin 11 , how minus 1 represented explanation?

you correct, normalized version of -1 in binary 1.100 0001

the problem type of maths no 1 it. you're going find hard find "experts" in field. 0.1 , 1.0 rules useful learning concept. conceptual rules don't apply in real world. point of normalization maintain accuracy possible within boundaries given. if make exponent 0010 complies rule... 1.010 0010 loosing accuracy (not in case of -1) potential there.