Complex question:

I have two inputs A & B from which I can calculate the output X plus the
error eX of the output:

That's no problem.

But I need to have it in a special scientific format:
(X +- eX) 10-Z cts/sec

Example: X = 2.3e-4, eX + 0.5e-4 then the output should be:
(2.3 +- 0.4) 10-4 cts/sec

The output should be in one cell.

How can a accomplish this?

Thanks a lot,
Andreas