# Decimal to Binary conversion

• Nov 1st 2009, 10:54 AM
ethio
Decimal to Binary conversion
Hello,
I need help in figuring out what im doing wrong:

-15.625 ---> 11110001.10100000 OR 11110001.101

but those turned out to be wrong.
any ideas?
• Nov 2nd 2009, 06:18 AM
Media_Man
Um, $-15.625=-(2^3+2^2+2^1+2^0+2^{-1}+2^{-3})=-(1111.101)_2$

Are you trying to "sign" it as a computer would, to store it in bytes? This is different than a strictly mathematical conversion.
• Nov 3rd 2009, 10:22 AM
ethio
Thats what i was looking for. -1111.101
thnx