# Can I deactivate block of cells in worksheet?

I have a worksheet where I first derive a bunch of equation and then use these equations for numerical computations and plotting. If I open the worksheet and want to run a new numerical computation using the same equations, I need to evaluate all the cells at the beginning of the notebook and then I can write my new numerical code and evaluate the new cell. To avoid going through each single cell and pressing Alt+Enter to evaluate, I'd like to use "Evaluate all" from the notebook menu, but this also evaluates all my other numerical cells, which takes an awful long time. Is there a way to 'deactivate' a block of cells in the worksheet, e.g. by turning them into a text block in the worksheet editing environment?

I was thinking about putting <html> before and <\html> after the cells but this did not work. Thanks for your help!