diff --git a/lib/binary_to_decimal.rb b/lib/binary_to_decimal.rb
index 439e8c6..e88932b 100644
--- a/lib/binary_to_decimal.rb
+++ b/lib/binary_to_decimal.rb
@@ -5,5 +5,44 @@
 # Calculate  and return the decimal value for this binary number using
 # the algorithm you devised in class.
 def binary_to_decimal(binary_array)
+  power_num = 0
+  index = -1
+  decimal_array = []
+  decimal_number = 0
+
+  binary_array.each do |num|
+    sum_of_nums = binary_array[index] * (2 ** power_num)
+    power_num += 1
+    index -= 1
+
+    decimal_array << sum_of_nums
+  end
+
+  decimal_array.each do |num|
+    decimal_number += num
+  end
+  return decimal_number
   raise NotImplementedError
 end
+
+def decimal_to_binary(decimal_number)
+  binary_array = []
+  reversed_array = []
+  index = -1
+
+  until decimal_number == 0
+    if decimal_number % 2 == 0
+      reversed_array << 0
+    else
+      reversed_array << 1
+    end
+    decimal_number /= 2
+  end
+
+  reversed_array.each do |num|
+    nums = reversed_array[index]
+    index -= 1
+    binary_array << nums
+  end
+  return binary_array
+end
diff --git a/test/binary_to_decimal_test.rb b/test/binary_to_decimal_test.rb
index ba17713..3395bb8 100644
--- a/test/binary_to_decimal_test.rb
+++ b/test/binary_to_decimal_test.rb
@@ -1,6 +1,6 @@
-require 'minitest/autorun'
-require 'minitest/reporters'
-require_relative '../lib/binary_to_decimal'
+require "minitest/autorun"
+require "minitest/reporters"
+require_relative "../lib/binary_to_decimal"
 
 describe "binary to decimal" do
   it "From 10011001 to 153" do
@@ -31,3 +31,20 @@
     binary_to_decimal(binary_array).must_equal expected_decimal
   end
 end
+describe "decimal to binary" do
+  it "Converts from 23 to 10111" do
+    decimal_number = 23
+    expected_bin_array = [1, 0, 1, 1, 1]
+    decimal_to_binary(decimal_number).must_equal expected_bin_array
+  end
+  it "Converts from 108 to 1101100" do
+    decimal_number = 108
+    expected_bin_array = [1, 1, 0, 1, 1, 0, 0]
+    decimal_to_binary(decimal_number).must_equal expected_bin_array
+  end
+  it "Converts from 1116 to 10001011100" do
+    decimal_number = 1116
+    expected_bin_array = [1, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0]
+    decimal_to_binary(decimal_number).must_equal expected_bin_array
+  end
+end