Hey Guys, Help Please (Ruby Basics)

Question

So i wanted to build a calculator and hit a dead end think any of u can help??

My Code:
def addition_function
puts "Which numbers would you like to add?"
@n1 = gets.chomp.to_i
@n2 = gets.chomp.to_i
@answer = @n1 + @n2
puts "The sum is... #{@answer}"
end

def subtraction_function
puts "Which numbers would you like to subtract?"
@n1 = gets.chomp.to_i
@n2 = gets.chomp.to_i
@answer = @n1 - @n2
puts "The answer is... #{@answer}"
end

def multiplication_function
puts "Which numbers would you like to multiply?"
@n1 = gets.chomp.to_i
@n2 = gets.chomp.to_i
@answer = @n1 * @n2
puts "The answer is... #{@answer}"
end

response = gets.chomp.to_i

if response == "add" then
addition_function
end
if response == "subtract" then
subtraction_function
end
if response == "multiply" then
multiplication_function
end