To calculate square roots for a range of cells simultaneously, you can apply an array formula. Select the range where you want the results to appear, enter '=SQRT(first_cell_of_original_range:last_cell_of_original_range)', and instead of pressing Enter, press Ctrl+Shift+Enter. Excel then processes the formula as an array formula, filling the selected range with the square roots of the corresponding cells in the original range. Remember, array formulas work differently in newer Excel versions (Office 365 and Excel 2019), where pressing Enter is sufficient.