No, 0.3 and 3.0 do not have the same value. The zero in front the decimal point, means that the next digit has a value less than one. The first decimal position is greater than the second decimal position, and it is greater than the fhird decimal positio, and so on; 0.3 is 3/10. The digit 3 in 3.0 has value of 3 units which is greater than 3/10.
