diff --git a/rmcervantes/roman_numerals.rb b/rmcervantes/roman_numerals.rb
new file mode 100644
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+++ b/rmcervantes/roman_numerals.rb
@@ -0,0 +1,33 @@
+class Roman_numerals
+	def initialize
+		@arabigos = {1000=>"M",900=>"CM",500=>"D",400=>"CD",100=>"C",90=>"XC",
+						50=>"L",40=>"XL",10=>"X",9=>"IX",5=>"V",4=>"IV",1=>"I"}
+		@romanos = {"I"=>1,"V"=>5,"X"=>10,"L"=>50,"C"=>100,"D"=>500,"M"=>1000}
+	end
+
+	def arab_to_rom(in_arabigo)
+		retorno = ""
+		@arabigos.each do |map_arabigo, map_romano|
+			if in_arabigo >= map_arabigo
+				in_arabigo -= map_arabigo
+				retorno += map_romano # concatenar romano
+				redo # volver a ejecutar este bucle
+			end
+		end
+		retorno # retornar resultado
+	end
+
+	def rom_to_arab(in_romano)
+		retorno = 0
+		anterior = @romanos[in_romano[0]] # inicia en el primer romano de la cadena
+		in_romano.each_char { |simbolo|
+			retorno += @romanos[simbolo]
+			if @romanos[simbolo] > anterior
+				# le quita el anterior sumado 2 veces (romano=IV => retorno = 1+5, fix: retorno = (1+5)-1-1)
+				retorno -= 2 * anterior
+			end
+  			anterior = @romanos[simbolo]
+		}
+		retorno # retornar resultado
+	end
+end
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diff --git a/rmcervantes/roman_numerals_rspec.rb b/rmcervantes/roman_numerals_rspec.rb
new file mode 100644
index 0000000..f7989ca
--- /dev/null
+++ b/rmcervantes/roman_numerals_rspec.rb
@@ -0,0 +1,98 @@
+require "rspec"
+require File.dirname(__FILE__) + "/roman_numerals.rb"
+
+describe Roman_numerals do
+	before do
+		@roman_numerals = Roman_numerals.new
+	end
+
+	describe "Arabigos a Romanos" do
+		it "que represente un solo simbolo" do
+			@roman_numerals.arab_to_rom(1).should eq("I")
+			@roman_numerals.arab_to_rom(5).should eq("V")
+			@roman_numerals.arab_to_rom(10).should eq("X")
+			@roman_numerals.arab_to_rom(50).should eq("L")
+			@roman_numerals.arab_to_rom(100).should eq("C")
+			@roman_numerals.arab_to_rom(500).should eq("D")
+			@roman_numerals.arab_to_rom(1000).should eq("M")
+		end
+
+		it "que represente simbolos repetidos" do
+			@roman_numerals.arab_to_rom(3).should eq("III")
+			@roman_numerals.arab_to_rom(30).should eq("XXX")
+			@roman_numerals.arab_to_rom(300).should eq("CCC")
+			@roman_numerals.arab_to_rom(3000).should eq("MMM")
+		end
+
+		it "que represente diferentes simbolos romanos" do
+			@roman_numerals.arab_to_rom(7).should eq("VII")
+			@roman_numerals.arab_to_rom(17).should eq("XVII")
+			@roman_numerals.arab_to_rom(67).should eq("LXVII")
+			@roman_numerals.arab_to_rom(367).should eq("CCCLXVII")
+			@roman_numerals.arab_to_rom(867).should eq("DCCCLXVII")
+			@roman_numerals.arab_to_rom(3867).should eq("MMMDCCCLXVII")
+		end
+
+		it "que represente conjuntos con resta de simbolos" do
+			@roman_numerals.arab_to_rom(4).should eq("IV")
+			@roman_numerals.arab_to_rom(9).should eq("IX")
+			@roman_numerals.arab_to_rom(40).should eq("XL")
+			@roman_numerals.arab_to_rom(90).should eq("XC")
+			@roman_numerals.arab_to_rom(400).should eq("CD")
+			@roman_numerals.arab_to_rom(900).should eq("CM")
+		end
+
+		it "que represente anios" do
+			@roman_numerals.arab_to_rom(1492).should eq("MCDXCII")
+			@roman_numerals.arab_to_rom(1990).should eq("MCMXC")
+			@roman_numerals.arab_to_rom(3999).should eq("MMMCMXCIX")
+			@roman_numerals.arab_to_rom(2008).should eq("MMVIII")
+		end
+	end
+
+	describe "Romanos a Arabigos" do
+		it "que represente un solo numero" do
+			@roman_numerals.rom_to_arab("I").should eq(1)
+			@roman_numerals.rom_to_arab("V").should eq(5)
+			@roman_numerals.rom_to_arab("X").should eq(10)
+			@roman_numerals.rom_to_arab("L").should eq(50)
+			@roman_numerals.rom_to_arab("C").should eq(100)
+			@roman_numerals.rom_to_arab("D").should eq(500)
+			@roman_numerals.rom_to_arab("M").should eq(1000)
+		end
+
+		it "en repeticiones" do
+			@roman_numerals.rom_to_arab("II").should eq(2)
+			@roman_numerals.rom_to_arab("XXX").should eq(30)
+			@roman_numerals.rom_to_arab("CC").should eq(200)
+			@roman_numerals.rom_to_arab("MMM").should eq(3000)
+		end
+
+		it "por union de diferentes simbolos romanos" do
+			@roman_numerals.rom_to_arab("VI").should eq(6)
+			@roman_numerals.rom_to_arab("VIII").should eq(8)
+			@roman_numerals.rom_to_arab("XI").should eq(11)
+			@roman_numerals.rom_to_arab("XVII").should eq(17)
+			@roman_numerals.rom_to_arab("LXVII").should eq(67)
+			@roman_numerals.rom_to_arab("CCLXVII").should eq(267)
+			@roman_numerals.rom_to_arab("DCCLXVII").should eq(767)
+			@roman_numerals.rom_to_arab("MMMDCCLXVII").should eq(3767)
+		end
+
+		it "para valores especiales (ex: IV IX XL)" do
+			@roman_numerals.rom_to_arab("IV").should eq(4)
+			@roman_numerals.rom_to_arab("IX").should eq(9)
+			@roman_numerals.rom_to_arab("XL").should eq(40)
+			@roman_numerals.rom_to_arab("XC").should eq(90)
+			@roman_numerals.rom_to_arab("CD").should eq(400)
+			@roman_numerals.rom_to_arab("CM").should eq(900)
+		end
+
+		it "que represente anios" do
+			@roman_numerals.rom_to_arab("MCDXCII").should eq(1492)
+			@roman_numerals.rom_to_arab("MCMXC").should eq(1990)
+			@roman_numerals.rom_to_arab("MMMCMXCIX").should eq(3999)
+			@roman_numerals.rom_to_arab("MMVIII").should eq(2008)
+		end
+	end
+end
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