Copying an array of ints to a float, and vis versa

Hi, I'm having a little trouble trying to figure this out, mostly because I don't really understand bitwise operators.

Let's say we have a integer array num with 10 elements filled with single digit numbers:

num[10]

num[0]: 1 num[6]: 9

num[1]: 2 num[7]: 3

num[2]: 6 num[8]: 0

num[3]: 7 num[9]: 1

num[4]: 0

num[5]: 4

So the number would be 1267049301.

If I had two of these types of arrays, I need to do arithmetic on them, like multiplying, addition, subtraction, ect. The only way I can see doing this is to make them floats, then do the arithmetic, and then change that number back into that array of integers. Now my question is, how would I do this? And if there's a easier way of doing this, I'd like to know that too.

Thanks for any help.