about the precision difference between raw data and its multiple data

  i have met a problem during writing a new hdf5 data with multiple factor for one of variables from origin hdf5 data.
for example,
I. the value of the origin variable var0 is equal to 0.27257, then i give it a multiple factor 10, its value change to 2.7257001, the difference appeared,
  if the value is equal to 0.253462, multiple 10, then correct value should be 2.53462, but the value from the output of hdf5 file is equal to 2.5346198, is not equal to 2.53462.
II. i changed the multiple factor to 0.1, the similar difference occurs.

can anybody tell me how to avoid this precision difference?