64.0 is the smallest decimal
0.0003 is the smallest decimal in this situation.
There is no smallest decimal - just as there is no largest number. If x was said to be the smallest decimal, inserting a zero immediately after the decimal point would give a number equal to a tenth of x - ie smaller than x.
There is no smallest decimal in the world because decimals can be infinitely small by adding more decimal places.
0.1 is the smallest positive number with 2 digits and a decimal point. without a decimal point the smallest is 10.
It is already a decimal that can also be expressed as 0.04
.001
0.001
0.08 is the smallest.
.04
.04
.04