error: Use of local variable 'resultTotFarina' before its declaration

the problem of the error is due to the fact that the indicated variables are indicated after but one depends on the other. how can i solve? I also tried to create some functions but I don't get the values. can you help me find the solution? Thank you.

the error is present in: let resultTotSale = numSale / (100 * resultTotFarina).

let resultTotFarina = resultPanetti - resultTotAcqua - Double(resultTotSale)

code: import UIKit

class DosiViewController: UIViewController{ ....

var numberPanetti = 0
var numberPeso = 0
var numberSale = 0
var numberAcqua = 0.0
var numberLievTa = 0
var numberTa = 0
var acquaInPerc = "0"
var totPanetti = "0"
var totFarina = "0"
var totSale = 0.0
var nettoPanetti = "0"
var totalPeso = 0
var totalAcqua = 0.0
var totalPanetti = 0

@IBAction func stepperPanettiValue(_ sender: UIStepper) {
    numeroPanetti.text = String(format: "%.0f", sender.value)
    numberPanetti = Int(sender.value)
}

@IBAction func stepperPesoValue(_ sender: UIStepper) {
    numeroPeso.text = String(format: "%.0f", sender.value)
    numberPeso = Int(sender.value)
}

@IBAction func stepperSale(_ sender: UIStepper) {
    numeroSale.text = String(format: "%.0f", sender.value)
    numberSale = Int(sender.value)
}

pizzas: I enter the number of blocks I enter the weight in grams I enter the percentage of salt I enter the percentage of water those calculations are used to have: total weight of the blocks. (number of blocks * weight) total percentage of salt to put on the dough. (flour to use: 100 * percentage of added salt)) total percentage of water. (flour to use: 100 * percentage of water added) total flour to use. (total blocks - water - salt)

example: 2 loaves of 50 gr.

total 100 grams of dough 50% water 23 grams of water 26 grams of flour 0.5 grams of salt 0.5 grams of yeast 

thank you