Hi,

Where did you get 33 bits?

The first (high order) bit is the sign bit. The next 8 bits form the biased exponent, then the next 23 bits form the normalized mantissa (leading bit is 1, not given).

So 4280 0000 hex yields in binary 0100 0010 1000 0000 and 16 more 0's

The sign bit is 0 (positive)

biased exponent 1000 0101 = 133, with the bias of 127, the true exponent is 6.

mantissa (including the hidden 1 bit) 1.000 and 16 more 0's

Finally, value is 2^{6}*1