Array Help for Korn Shell Script

I am using three different arrays for a script I am writing, and then I subtracting array1 from array2 to create array3. I have this working but array1 and array2 are have decimals points, and when array3 is created it drops off the decimals, for example 1.55 - 1.4 = .15, but I get 0. Now I have done calculations before and had to use 'typeset -F2 xxxx' to cause the variables to be floating point, but I don't know how to get an array to be floating point. Any suggestions?

Thanks, Brian