重複のない整数対の配列を作る

random_problem.rb

def nn
  (rand * 5).to_i + 1
end

def random_problem(n)
  a = []
  while a.length < n do
    a.push [nn,nn]
    a.uniq!
  end
  a.each do |e|
    puts "$#{e[0]} + #{e[1]} = $ \n\n  \\vfill"
  end
end