When I try to use the following methods nothing gets returne

When I try to use the following methods, nothing gets returned. How do I fix this?

import java.util.*;

public class Grades
{

public boolean validGrade()
{
Scanner input = new Scanner(System.in);
System.out.println(\"Please enter your numeric grade: \");
int numGrade = input.nextInt();
  
return numGrade >= 0 && numGrade <= 100);
}
  

//assuming the grade is valid (between 0 & 100 inclusive)
public char getLetterGrade()
{
Scanner input = new Scanner(System.in);
System.out.println(\"Please enter your numeric grade: \");
int numGrade = input.nextInt();
  
if(numGrade >= 90)
{
return \'A\';
}
else if(numGrade >= 80)
{
return \'B\';
}
else if(numGrade >= 70)
{
return \'C\';
}
else if(numGrade >= 60)
{
return \'D\';
}
else
{
return \'F\';
}
}
}

Solution

The working code is

//*******************************************************************
// NOTE: please read the \'More Info\' tab to the right for shortcuts.
//*******************************************************************
//importing package io as we are using scanner class
//created main function
//
import java.util.*;
import java.io.*;
public class Grades
{
public boolean validGrade()
{
Scanner input = new Scanner(System.in);
System.out.println(\"Please enter your numeric grade: \");
int numGrade = input.nextInt();
if(numGrade>=0 && numGrade<=100)//added a condition to check wheter a grade is valid or not.If invalid return false else true
return true;
return false;
}
  
//assuming the grade is valid (between 0 & 100 inclusive)
public char getLetterGrade()
{
Scanner input = new Scanner(System.in);
System.out.println(\"Please enter your numeric grade: \");
int numGrade = input.nextInt();
  
if(numGrade >= 90)
{
return \'A\';
}
else if(numGrade >= 80)
{
return \'B\';
}
else if(numGrade >= 70)
{
return \'C\';
}
else if(numGrade >= 60)
{
return \'D\';
}
else
{
return \'F\';
}
}
  
  
public static void main(String... s){
  
Grades t=new Grades();
System.out.println(t.validGrade());
System.out.println(t.getLetterGrade());
  
}
}