quiz.rb

OPERATORS = ['+', '-']
ROUNDS = 2
MAX_NUMBER = 9

puts 'What is your name?'
name = gets.chomp
puts "Welcome to Arithmetic Tutor, #{name}!"

results = (1..ROUNDS).map do 
  left = rand(MAX_NUMBER + 1)
  right = rand(MAX_NUMBER + 1)
  op = OPERATORS.sample
  correct_answer = left.send(op, right)

  print "What is #{left} #{op} #{right}? "
  answer = gets.to_i

  [left, op, right, answer == correct_answer]
end

num_correct = results.select{ |r| r.last }.size
puts "SCORE: #{num_correct}/#{results.size}."
puts "Your results were as follows:"
results.each do |(left, op, right, correct)|
  puts "What is #{left} #{op} #{right}? #{correct ? 'CORRECT' : 'INCORRECT'}"
end