diff --git a/calculator.rb b/calculator.rb
new file mode 100644
index 0000000..8716caa
--- /dev/null
+++ b/calculator.rb
@@ -0,0 +1,85 @@
+def add(num_1, num_2)
+  return num_1 + num_2
+end
+
+def subtrat(num_1, num_2)
+  return num_1 - num_2
+end
+
+def multiply(num_1, num_2)
+  return num_1 * num_2
+end
+
+def divide(num_1, num_2)
+  return num_1 / num_2
+end
+
+def exponify(num_1, num_2)
+  return num_1 ** num_2
+end
+
+def modulus(num_1, num_2)
+  return num_1 % num_2
+end
+
+operator_array = %w[Add + Subtract - Multiply * Divide / Exponify ^ Modulus % 1 2 3 4 5 6]
+
+puts "Welcome to the calculator! Time to do some math."
+puts "\nWhich operator would you like to use?"
+
+puts "1. Add (+)"
+puts "2. Subtract (-)"
+puts "3. Multiply (*)"
+puts "4. Divide (/)"
+puts "5. Exponify (^)"
+puts "6. Modulus (%)"
+
+user_operator = gets.chomp.capitalize
+until operator_array.include?(user_operator)
+  puts "Please enter a valid operator."
+  user_operator = gets.chomp.capitalize
+end
+
+puts "\nWhat number would you like to have be first?"
+num_1 = gets.chomp
+if (num_1 != 0) && (num_1.to_s.to_f == 0.0)
+  puts "Please input a valid number, or input 0 again."
+  num_1 = gets.chomp
+end
+
+puts "\nWhat number would you like to have be second?"
+num_2 = gets.chomp
+if (num_2 != 0) && (num_2.to_s.to_f == 0.0)
+  puts "Please input a valid number, or input 0 again."
+  num_2 = gets.chomp
+end
+
+num_1 = num_1.to_f
+num_2 = num_2.to_f
+
+puts "\nRESULT: "
+
+case user_operator 
+  when "Add", "+", "1"
+    result = add(num_1, num_2)
+    puts "#{num_1} + #{num_2} = #{result}"
+  when "Subtract", "-", "2"
+    result = subtrat(num_1, num_2)
+    puts "#{num_1} - #{num_2} = #{result}"
+  when "Multiply", "*", "3"
+    result = multiply(num_1, num_2)
+    puts "#{num_1} * #{num_2} = #{result}"
+  when "Divide", "/", "4"
+    result = divide(num_1, num_2)
+    if num_2 == 0
+      puts "Err"
+    elsif
+      puts "#{num_1} / #{num_2} = #{result}"
+    end
+  when "Exponify", "^", "5"
+    result = exponify(num_1, num_2)
+    puts "#{num_1}^#{num_2} = #{result}"
+  when "Modulus", "%", "6"
+    result = modulus(num_1, num_2)
+    puts "#{num_1} % #{num_2} = #{result}"
+end