So I assume you are trying to center your data to 200.
It's similar to a standardization where you subtract the mean of the samples across your samples to get a constant mean of 0.
To get a constant mean of 200, you can add (200 - mean) across your samples. For example if one of your rows look like this:
geneX 50 10 20 40
The mean for this gene is 30. To make the mean 200, you just add a constant of 170 (200 - mean) to each number:
geneX 220 180 190 210