input: Write a python function to find all pairs of numbers in a list that sum to a given target.
  assert sum_to_target([2, 5, 3, 8, 11], 9) == [(2, 7), (3, 6), (5, 4)]
  assert sum_to_target([1, 2, 3, 4, 5], 5) == [(1, 4), (2, 3)]
  assert sum_to_target([10, 20, 30, 40, 50], 60) == [(10, 50), (20, 40)]
output: def sum_to_target(numbers, target):
      pairs = []
      seen = set()
      for number in numbers:
          complement = target - number
          if complement in seen:
              pairs.append((complement, number))
          seen.add(number)
      return pairs