def all_formula_values(precision = 14)
      formulas = []
      worksheets.each do |c_sheet|
        next unless c_sheet

        c_sheet.rows.each do |c_row|
          next unless c_row

          c_row.cells.each do |c_cell|
            next unless c_cell
            next unless c_cell.formula
            next if c_cell.formula.empty?

            text = c_cell.raw_text
            if StringHelper.numeric?(text)
              text = text.to_f.round(10).to_s[0..precision]
            elsif StringHelper.complex?(text)
              complex_number = Complex(text.tr(',', '.'))
              real_part = complex_number.real
              real_rounded = real_part.to_f.round(10).to_s[0..precision].to_f

              imag_part = complex_number.imag
              imag_rounded = imag_part.to_f.round(10).to_s[0..precision].to_f
              complex_rounded = Complex(real_rounded, imag_rounded)
              text = complex_rounded.to_s
            end
            formulas << text
          end
        end
      end
      formulas
    end
def all_formula_values(precision = 14)
      formulas = []
      worksheets.each do |c_sheet|
        next unless c_sheet

        c_sheet.rows.each do |c_row|
          next unless c_row

          c_row.cells.each do |c_cell|
            next unless c_cell
            next unless c_cell.formula
            next if c_cell.formula.empty?

            text = c_cell.raw_text
            if StringHelper.numeric?(text)
              text = text.to_f.round(10).to_s[0..precision]
            elsif StringHelper.complex?(text)
              complex_number = Complex(text.tr(',', '.'))
              real_part = complex_number.real
              real_rounded = real_part.to_f.round(10).to_s[0..precision].to_f

              imag_part = complex_number.imag
              imag_rounded = imag_part.to_f.round(10).to_s[0..precision].to_f
              complex_rounded = Complex(real_rounded, imag_rounded)
              text = complex_rounded.to_s
            end
            formulas << text
          end
        end
      end
      formulas
    end
Get all values of formulas.
 @param [Fixnum] precision of formulas counting
 @return [Array, String] all formulas