You are correct. The numerals written to the right of the point (.) in an octal number are coefficients of negative powers of 8. Thus, 13.48 would be expanded as
13.48 = 1(81) + 3(80) + 4(8 − 1).
We should recall that
8 − 1 = (1)/(81) = (1)/(8).
So we can find the decimal equivalent of our octal 13.48 as follows:
