I think you can always compress compressed data, is that true?

In compressed data, repetition of the same pattern is not much, therefore, you can expect it to be with interior space to always contain. I have found a way to compress the data without limitation. It is right? Am I thinking the true way?

BigNumber = BigNumber * N + LittleBitsNumber (=> smaller than N)
Delete that number of data bits / file

Thank you!