Mensa number question

mensa_number.rb

#!/usr/bin/env ruby

# Find a SIX digit number in which the FIRST digit is ONE more than the THIRD,
# the SECOND digit is ONE less than the FOURTH, the FIFTH digit is ONE less than
# the THIRD, and the SIXTH digit is ONE more than the FOURTH. The sum of the
# SECOND and THIRD digits equal the FIRST. The sum of all digits is 30.

# Returns 6 digit numbers that the sum of the digits are 30
def possible_numbers
  numbers = []
  num = 0
  while num <= 999999 do
    numbers << "%06d" % num if num.to_s.each_char.map {|c| c.to_i }.reduce(:+) == 30
    num += 1
  end
  return numbers
end

# Filter number_array to only return numbers that digit in position_one == digit in position_two op 1
def filter_numbers(position_one, position_two, op, number_array)
  number_array.each_with_object([]) do |number, numbers|
    numbers << number if number.chars[position_one-1].to_i == number.chars[position_two-1].to_i.send(op, 1)
  end
end

# Filter number_array to only return numbers that digit 2 and digit 3 add up to digit 1
def the_sum_of_second_and_third_is_the_first(number_array)
  number_array.each_with_object([]) do |number, numbers|
    numbers << number if (number.chars[1].to_i + number.chars[2].to_i) == number.chars[0].to_i
  end
end

# you could futher simplify this by chaining everything (but its kinda hard to read)
 puts(
  the_sum_of_second_and_third_is_the_first(
    filter_numbers( 6, 4, "+",
      filter_numbers( 2, 4, "-",
        filter_numbers( 5, 3, "-",
          filter_numbers( 1, 3, "+",
            possible_numbers
          )
        )
      )
    )
  )
)

Should have called the filter_numbers method enhance