def soma(p1, p2)
  p1 + p2
end

def substrai(p1, p2)
  p1 - p2
end

def multiplica(p1, p2)
  p1 * p2
end

puts soma(10, 10) == 20
puts soma(10, 5) == 15

puts substrai(10, 5) == 5
puts multiplica(5, 5) == 25