Why 1.01 equals -0.75 in Q2 I'm trying to learn Q notation but I don't understand why 1.01 in the Q2 number format equals -0.75. How is that calculation done? I can understand that 1.1 equals -0.5 because the leading 1 means the number is negative and the first digit after the binary point is 1 which means 1*2^(-1) which is 0.5 and therefore the number is -0.5. Similarly, 1.01 should equal -0.25 and not -0.75.

It is 1.11 which is -0.75 or what is my mistake?
$$1\times (-1)+0\times2^{-1}+1\times2^{-2}=-0.75$$