I have created formulas for a very large matrix of cells represented below
such that (sheet1):
B10 = A1-A1 C10 = B1-A1 D10 = C1-A1 .......
B11 = A1-B1 C11 = B1-B1 D11 = C1-B1 .......
many more rows and columns:)

Although these formulas are correct - they each needed to be typed in by
hand. To do the analysis of error propagation on the data the formulas will
use the same cell numbers in question, however, the formula will change such
that as per given example (sheet 2)

C10 = ((B1^2)+(A1^2)) ^(1/2)

Is there a method for editing the formula only for a mass group of cells
while keeping the cells they refer to the same?

It is not possible with the matrix layout to autofill - and editing each
individual formula is very tedious with large amounts of data.

Also for future reference: is there an autofill for the single cell
increase while the other remains constant as in row 10 in the example above?

Thanks,
Jen