In order to create a multiplication with the least possible result, we need small numbers for both factors.
For the first number, we can start with 2 and use 5 and 7 for decimal places (let's save number 4 to use in the second number), so we have the number 2.57.
For the second number, we have just the numbers 4 and 8, so we have the number 4.8.
The product of these numbers is: