Decimals are a type of fractional number. It can have a denominator of a power of 10, and it can be 100. The 0.5 represents the fraction 5/10 because we put 1 in place of decimal in the denominator and the values after decimal in the numerator becomes 0 in the denominator. That's why 0.5 becomes 5/10.
Like wise if we have decimal value of 2.55 than the fractional notation of this number would be 255/100.
