diff --git a/ruby/2019/1/bin/problem b/ruby/2019/1/bin/problem
new file mode 100644
index 0000000..7bb738b
--- /dev/null
+++ b/ruby/2019/1/bin/problem
@@ -0,0 +1,7 @@
+#!/usr/bin/env ruby
+
+require "rocket_equation"
+rockets = STDIN.read.chomp.split("\n").map { |line| RocketEquation.for line }
+puts "Part 1: #{rockets.map(&:fuel_required).sum}"
+puts "Part 2: #{rockets.map(&:more_fuel_required).sum}"
+
diff --git a/ruby/2019/1/lib/rocket_equation.rb b/ruby/2019/1/lib/rocket_equation.rb
new file mode 100644
index 0000000..46beb6e
--- /dev/null
+++ b/ruby/2019/1/lib/rocket_equation.rb
@@ -0,0 +1,20 @@
+class RocketEquation
+  attr_reader :mass
+  def initialize(mass)
+    @mass = mass
+  end
+
+  def self.for(line)
+    new line.to_i
+  end
+
+  def fuel_required
+    [(mass / 3) - 2, 0].max
+  end
+
+  def more_fuel_required
+    return 0 unless mass.positive?
+
+    fuel_required + RocketEquation.new(fuel_required).more_fuel_required
+  end
+end
diff --git a/ruby/2019/1/main.rb b/ruby/2019/1/main.rb
deleted file mode 100644
index 73d0afa..0000000
--- a/ruby/2019/1/main.rb
+++ /dev/null
@@ -1,46 +0,0 @@
-class Module
-  attr_reader :mass
-  def initialize(mass)
-    @mass = mass
-  end
-
-  def fuel_required
-    (mass / 3) - 2
-  end
-
-  def self.for(string)
-    new(string.to_i)
-  end
-end
-
-class Modules
-  attr_reader :modules
-  def initialize(modules)
-    @modules = modules
-  end
-
-  def self.from_file(filename, module_type)
-    new(File.read(filename).split.map{ |mass| module_type.for mass })
-  end
-
-  def total_fuel_required
-    @modules.map(&:fuel_required).sum
-  end
-end
-
-class HeavyFuelModule < Module
-  def fuel_required
-    super + Fuel.new(super).fuel_required
-  end
-end
-
-class Fuel < Module
-  def fuel_required
-    return 0 if super < 0
-
-    super + Fuel.new(super).fuel_required
-  end
-end
-
-puts "Part 1: #{Modules.from_file("../data/2019/1/input.txt", Module).total_fuel_required}"
-puts "Part 2: #{Modules.from_file("../data/2019/1/input.txt", HeavyFuelModule).total_fuel_required}"
diff --git a/ruby/2019/1/test/test_rocket_equation.rb b/ruby/2019/1/test/test_rocket_equation.rb
new file mode 100644
index 0000000..819f8d4
--- /dev/null
+++ b/ruby/2019/1/test/test_rocket_equation.rb
@@ -0,0 +1,26 @@
+require "minitest/autorun"
+require "rocket_equation"
+
+class TestRocketEquation < Minitest::Test
+  def assert_fuel_required(fuel, mass)
+    assert_equal(fuel, RocketEquation.for(mass).fuel_required)
+  end
+
+  def test_fuel_required
+    assert_fuel_required(2, 12)
+    assert_fuel_required(2, 14)
+    assert_fuel_required(654, 1969)
+    assert_fuel_required(33583, 100756)
+  end
+
+  def assert_more_fuel_required(fuel, mass)
+    assert_equal(fuel, RocketEquation.for(mass).more_fuel_required)
+  end
+
+  def test_more_fuel_required
+    assert_more_fuel_required(2, 12)
+    assert_more_fuel_required(2, 14)
+    assert_more_fuel_required(966, 1969)
+    assert_more_fuel_required(50346, 100756)
+  end
+end