Error CS1513 (quick question)

To add to what TheRealSteveJudge said: you are not using brackets properly anyway.

Console.WriteLine("whats 9+45?");
{
    if (Answer == 54);
    { Console.WriteLine("{0} {1} is Smart! :D ");
    } <===== //it asks me to put a '}' after the'}'

 else
   { Console.WriteLine("{0} {1} isn't so Smart :( ");
    }
    Console.WriteLine("Press Enter to Close");

    Button = Console.ReadLine();
}

You don't need the outer set brackets here - they don't serve any purpose. You only use them when you are "grouping together" statements to be executed - in a method for example, a loop, or a conditional statement. Adding them "at random" doesn;t make your code more readable!

As a beginner, use them for every conditional, and indent your code:

static void Main(string[] args)
    {
    Console.WriteLine("what is your name?");
    string Name = Console.ReadLine();
    Console.WriteLine("what is your family name?");
    string Family = Console.ReadLine();
    int Answer = 54;

    Console.WriteLine("whats 9+45?");
    if (Answer == 54)
        {
        Console.WriteLine("{0} {1} is Smart! :D ");
        }
    else
        {
        Console.WriteLine("{0} {1} isn't so Smart :( ");
        }
    Console.WriteLine("Press Enter to Close");

    string Button = Console.ReadLine();
    }

Or like this:

static void Main(string[] args)
{
    Console.WriteLine("what is your name?");
    string Name = Console.ReadLine();
    Console.WriteLine("what is your family name?");
    string Family = Console.ReadLine();
    int Answer = 54;

    Console.WriteLine("whats 9+45?");
    if (Answer == 54)
    {
        Console.WriteLine("{0} {1} is Smart! :D ");
    }
    else
    {
        Console.WriteLine("{0} {1} isn't so Smart :( ");
    }
    Console.WriteLine("Press Enter to Close");

    string Button = Console.ReadLine();
}

Note that I moved the definition of variables to where you are going to use them - that just makes it easier to see what is going on when you actually use them. With small methods like this, that doesn't make a lot of difference, but as they grow it becomes a pain to wade back through pages of code to find the definition. It also prevents you using them when they are "out of scope" and the error messages that causes.

In addition, names of local variables should start with lower case:

        static void Main(string[] args)
            {
            Console.WriteLine("what is your name?");
            string name = Console.ReadLine();
            Console.WriteLine("what is your family name?");
            string family = Console.ReadLine();
            int answer = 54;
...

And your next problem is your WriteLine statements:

    Console.WriteLine("{0} {1} is Smart! :D ");
    }
else
    {
    Console.WriteLine("{0} {1} isn't so Smart :( ");
    }

You tell the writeline to include variable values, but you don't supply the variables! Either do this:

    Console.WriteLine("{0} {1} is Smart! :D ", name, family);
    }
else
    {
    Console.WriteLine("{0} {1} isn't so Smart :( ", name, family);
    }

Or this

    Console.WriteLine($"{name} {family} is Smart! :D ");
    }
else
    {
    Console.WriteLine($"{name} {family} isn't so Smart :( ");
    }

If you are using a recent version of Visual Studio.

Advice: Learn to indent properly your code, it show its structure and it helps reading and understanding. It also helps spotting structures mistakes.

using System;

namespace ConsoleApp1
{
  class Program
  {
    static void Main(string[] args)
    {
      string Name;
      string Family;
      string Button;
      int Answer;
      Answer = 54;


      Console.WriteLine("what is your name?");

      Name = Console.ReadLine();

      Console.WriteLine("what is your family name?");

      Family = Console.ReadLine();

      Console.WriteLine("whats 9+45?");
      {
        if (Answer == 54); // semicolumn here is mistake
        {
          Console.WriteLine("{0} {1} is Smart! :D ");
        } <===== //it asks me to put a '}' after the'}'

        else
        {
          Console.WriteLine("{0} {1} isn't so Smart :( ");
        }
        Console.WriteLine("Press Enter to Close");

        Button = Console.ReadLine();
      }
    }
  }
}

Professional programmer's editors have this feature and others ones such as parenthesis matching and syntax highlighting.
Notepad++ Home[^]
ultraedit[^]
Indentation style - Wikipedia[^]