from ironxl import *

# Load the Excel workbook
workbook = WorkBook.Load("sample.xlsx")
worksheet = workbook.DefaultWorkSheet

# Set Formulas
worksheet["A1"].Formula = "Sum(B8:C12)"
worksheet["B8"].Formula = "=C9/C11"
worksheet["G30"].Formula = "Max(C3:C7)"

# Force recalculate all formula values in all sheets.
workbook.EvaluateAll()

# Get the formula's calculated value. e.g. "52"
formula_value = worksheet["G30"].ToArray()[0].FormattedCellValue

# Get the formula as a string. e.g. "Max(C3:C7)"
formula_string = worksheet["G30"].Formula

# Save changes with updated formulas and calculated values.
workbook.Save()