Why does my formula turn grey when trying to link data from one sheet to the other..???

Hi there... 

I have been trying to put data from one excel sheet on another

I do not want to copy paste cause I want it to stay connected

Therefore, using = and selecting the cells I want to copy from one sheet to the other

However, now what happens is that it is pasted in such a way where the formula turns grey and i can't make any changes (e.g. deleting a column)...

I used to never have this problem

So what can I do to simply copy the values into another sheet, while it still says / shows the location of the other sheet, but the formula is black / i can make changed

Hope this makes sense