diff --git a/calculator.rb b/calculator.rb
new file mode 100644
index 0000000..882fafa
--- /dev/null
+++ b/calculator.rb
@@ -0,0 +1,84 @@
+# This is a calculator program
+
+# Define methods
+
+def add(num_one, num_two)
+  return num_one + num_two
+end
+
+def subtract(num_one, num_two)
+  return num_one - num_two
+end
+
+def multiply(num_one, num_two)
+  return num_one * num_two
+end
+
+def divide(num_one, num_two)
+  return num_one / num_two
+end
+
+def exponent(num_one, num_two)
+  return num_one ** num_two
+end
+
+possible_operations = ["ADD", "SUBTRACT", "DIVIDE", "MULTIPLY", "EXPONENT", "+", "-","/", "*", "^"]
+
+# Get user input for the operation to perform
+# Ask for user input until operation is valid
+puts "Which operation would you like to perform?"
+print "(Add, Subtract, Multiply, Divide, Exponent) "
+operation = gets.chomp.upcase
+  until possible_operations.include?(operation)
+    puts "That is an invalid operation. Try again"
+    operation = gets.chomp.upcase
+  end
+
+# Get user input for numbers
+# Ask for input until user enter integer
+puts "Okay, please enter a number."
+  num_one = gets.chomp
+    while num_one.to_i.to_s != num_one
+      puts "That is not a valid number. Please try again."
+      num_one = gets.chomp
+    end
+
+num_one = num_one.to_i
+
+
+puts "Please enter another number."
+num_two = gets.chomp
+
+while num_two.to_i.to_s != num_two
+  puts "That is not a valid number. Please try again."
+  num_two = gets.chomp
+end
+
+num_two = num_two.to_i
+
+# Perform calculations
+if operation == "ADD" || operation == "+"
+  sum = add(num_one, num_two)
+  puts "#{num_one} + #{num_two} = #{sum}"
+  return sum
+elsif operation == "SUBTRACT" || operation == "-"
+  sum = subtract(num_one, num_two)
+  puts "#{num_one} - #{num_two} = #{sum}"
+  return sum
+elsif operation == "MULTIPLY" || operation == "*"
+  sum = multiply(num_one, num_two)
+  puts "#{num_one} * #{num_two} = #{sum}"
+  return sum
+elsif operation == "DIVIDE" || operation == "/"
+  sum = divide(num_one, num_two)
+  puts "#{num_one} / #{num_two} = #{sum}"
+  return sum
+elsif operation == "EXPONENT" || operation == "^"
+  sum = exponent(num_one, num_two)
+  printing_exponent = num_two - 1
+  print "#{num_one}^#{num_two} = "
+  print num_one
+  printing_exponent.times { print " * #{num_one}"}
+  print " = #{sum}\n"
+  return sum
+end