I get #NUM! error if I edit the cells in row 2 and 3. Error will be in the corresponding row below that certain edited cell.

Here is the script:

Main:

    function onEdit(e) {
  doFirstThing_(e);
  doSecondThing_(e);
}

Then the first function

// Define the original quantities of the ingredients for the recipe
var originalQuantitiesFirst = [1, 1, 2, 2, 1, 1];  // Couscous, Teff, Fig, Date, Hamburg

function doFirstThing_(e) {
  // Get the active spreadsheet
  var spreadsheet = e.source;
  
  // Get the sheet named 'Valencia'
  var sheet = spreadsheet.getSheetByName('Valencia');
  
  // Check if the edited cell is in the 'Quantity' column (Column B, D, F, H, or J in this case)
  if (["B3", "D3", "F3", "H3", "J3", "F2"].includes(e.range.getA1Notation())) {
    // Get the new quantity
    var newQuantity = e.value;

  // Log the new quantity
  console.log('New quantity in doFirstThing_: ' + newQuantity);
 
  // Calculate the ratio of new quantity to original quantity of the changed ingredient
  var ingredientIndex = ["B3", "D3", "F3", "H3", "J3", "F2"].indexOf(e.range.getA1Notation());
  var ratio = newQuantity / originalQuantitiesFirst[ingredientIndex];
    
    // Define the cells with the quantities
    var quantityCells = ["B3", "D3", "F3", "H3", "J3", "F2"];
    
    // Loop through each quantity cell
    for (var i = 0; i < quantityCells.length; i++) {
      // Update the quantity based on the ratio and the original quantity
  var newQuantity = originalQuantitiesFirst[i] * ratio;
      
      // Update the cell with the new quantity
      sheet.getRange(quantityCells[i]).setValue(newQuantity);
    }
  }
}

Last function:

// Define the original quantities of the ingredients for all recipes
var originalQuantities = [[1, 3, 6, 4, 1], [1, 1, 3, 1, 1], [5, 3, 2, 3, 1], [4, 5, 1, 2, 1], [3, 2, 4, 4, 1]];  // Stew, Nutmeg, Dough, Vegetables, Bread, Scorpion, Sauce, Stew, Fig, Sugar, Oil, Dough, Agent, Date, Sugar, Liquor, Nutmeg, Pickle, Meat, Bread

function doSecondThing_(e) {
  // Get the active sheet
  var sheet = e.source.getActiveSheet();
  
  // Check if the edited cell is in the 'Quantity' column (Column B, D, F, H, or J in this case)
  // and the sheet is 'Valencia'
  if ([2, 4, 6, 8, 10].includes(e.range.columnStart) && sheet.getName() == 'Valencia') {
    // Get the new quantity
    var newQuantity = e.value;
  
  // Log the new quantity
  console.log('New quantity in doSecondThing_: ' + newQuantity);
   
    // Calculate the ratio of new quantity to original quantity of the changed ingredient
    var recipeIndex = Math.floor(e.range.columnStart / 2) - 1;
    var ratio = newQuantity / originalQuantities[recipeIndex][e.range.rowStart - 4];  // Adjusted for the new row start
    
    // Get the range of cells with the quantities
    var startColumn = String.fromCharCode(66 + recipeIndex * 2);  // 66 is the ASCII value for 'B'
    var quantityRange = sheet.getRange(startColumn + "4:" + startColumn + "8");  // Adjusted for the new row start and end
    
    // Get the values of the cells in the range
    var quantities = quantityRange.getValues();
    
    // Loop through each quantity
    for (var i = 0; i < quantities.length; i++) {
      // Update the quantity based on the ratio and the original quantity
      quantities[i][0] = originalQuantities[recipeIndex][i] * ratio;
    }
    
    // Update the cells in the range with the new quantities
    quantityRange.setValues(quantities);
  }
}

If I edit the cells from row 4 and below, no error on top of that cell. I tried logging it but the error is

TypeError: Cannot read properties of undefined (reading
‘getA1Notation’)
at doFirstThing_(Script1:12:61) at onEdit(Main:2:3)