title: replacing an element in nested array ruby
body: <p>I'm having trouble locating where my issue is in my code. I want to replace specific elements with 'X' if they show up on a bingo board:</p>
  
  <pre><code>class BingoBoard
  
    def initialize(board)
      @bingo_board = board
    end
  
    def number_letter
  
      @letter = ['B','I','N','G','O'].sample
      @number = rand(1..100)
  
    end
  
    def checker
      @number
      @bingo_board.map! do |n|
  
        if n.include?(@number)
  
          n.map! { |x| x == @number ? 'X' : x}
  
        else
  
          n
  
        end
      end
  
    end
  
  end
  </code></pre>
  
  <p>this is the test i'm using to see if my code is running, but X never shows up and I been looking over my code many times now and can't figure out why...:</p>
  
  <pre><code>board = [[47, 44, 71, 8, 88],
          [22, 69, 75, 65, 73],
          [83, 85, 97, 89, 57],
          [25, 31, 96, 68, 51],
          [75, 70, 54, 80, 83]]
  
  new_game = BingoBoard.new(board)
  
  new_game.checker
  </code></pre>
  
  <p>If anyone can provide insight on what I am missing or not seeing, I would greatly appreciate it!</p>