"The name 'Convert' does not exist in the current context" C#

I am trying to use Input Field boxes for multiplying the given input from the user. I need to change the string into an integer form so i can multiply it, then i need change it back to a string once it is multiplied so the answer can be displayed. (or at least i think that’s how it should work)

I have 2 questions, How can i fix this error: Assets/Calculations.cs(20,25): error CS0103: The name `Convert’ does not exist in the current context

and 2, how can i call from my own Input Field boxes instead of what i have in the example script? The script i have is a very rough idea of what i need to do.

using UnityEngine;
using UnityEngine.UI;
using System.Collections;

public class Calculations : MonoBehaviour {

	public InputField Field1;
	public InputField Field2;
	public Text Result;
	
//	public void Sum() {
//		int a = Convert.ToInt32(Field1.text);
//		int b = Convert.ToInt32(Field2.text);
//		int c = a+b;
//		Result.text = c.ToString();
//	}
	
	
	public void Product() {
		int a = Convert.ToInt32(Field1.text);
		int b = Convert.ToInt32(Field2.text);
		int c = a*b;
		Result.text = c.ToString();
	}
	
}

As the other answer reads, put

using System;

At the top.

You did well with using UnityEngine.UI;

In order to get your text fields’ data in, try this:

//Top of the script

public GameObject textField_1;
public GameObject textField_2; //drag these game objects into the script via the inspector.
InputField t1;
InputField t2;

void Start()
{
t1 = textField_1.GetComponent<InputField>();
t1 = textField_2.GetComponent<InputField>();
}

     public void Product() {
         int a = Convert.ToInt32(t1.text);
         int b = Convert.ToInt32(t2.text);
         int c = a*b;
         Result.text = c.ToString();
     }

Convert exists in System namespace so you either have to call it using:

System.Convert.ToInt32

or import the namespace with:

using System;

at the top.