# Binary 2's complement to decimal

I need to transform 2's complement from binary to decimal

The binary integer is 10001001

This is my thought process. Could someone validate my thought process or correct it, please?

10001001 it is a negative integer as the sign magnitude is 1.
Toggle the bits: 01110110

• If number of digits is $8$, then your calculations are correct. – zkutch Feb 9 at 10:53