plusminus.rb

system('clear')
begin
  runs, score = 0, 0
  3.times do
    add, (i1, i2) = rand(2).zero?, [rand(750), rand(250)].sort

    sym, answer = if add
      ['+', (i1 + i2)]
    else
      ['-', (i2 - i1)]
    end

    print "Question: #{i2} #{sym} #{i1} = ?\n"
    print 'Enter your answer: '
    candidate = gets

    runs += 1
    if candidate.strip.to_i == answer
      score += 1
      print "Correct!"
    else
      print "Incorrect. The correct answer was #{answer}."
    end

    print "\nScore is now #{score}/#{runs}"
    print "\n\n\n"
  end 
rescue Interrupt => e
  print "\nTest stopped at score #{score}/#{runs}"
  exit
end
print "\nTest complete! Score #{score}/#{runs}\n"