Single-precision floating-point format $2^{-23}$

Question

In some lecture note I saw the following :

"The distance between two consecutive mantissas is $2^{-23}$"

What can it possible mean?

Answer 1

In single precision numbers (32 bits), they use 1 bit for sign, 8 bits for the exponent and 23 bits for the mantissa. Mantissa is a number made out from negative powers of $2$, so the smallest is $2^{-23}$. The largest mantissa is formed by 23 digits of $1$, which is about $1$