Locking range start when adding new rows

Hello everyone and I hope you can help me. I am new to this site.

I have data in cells A1:A10 and perform a calculation on that data series, the result of which is displayed on another sheet. I then have new data to add to the series and include in the calculation, so I insert a cell at A1 and add my new data. For convenience I do want to add the new data at the start of the series, not the end. The calculation is now performed on cells A2:A11, but I want it to be performed on A1:A11 How can I lock the start of the range as cell A1, so I don't have to manually update the formula? Of course, absolute cell referencing doesn't work and I have tried to use the offset function without success as well.

Hope you can help.