diff --git a/Harder/Advanced-Calculator.md b/Harder/Advanced-Calculator.md
new file mode 100644
index 0000000..02638c3
--- /dev/null
+++ b/Harder/Advanced-Calculator.md
@@ -0,0 +1,87 @@
+# 12.6 Advanced Calculator
+
+## The task
+Create a calculator. That will be able to take user input of an math operation and perform it.
+
+But it would be a little advanced from other python calculator projects those you usually see. 
+
+It will take the calculation directly from the user and then perform it, without asking user to choose operation type( addition, multiplication etc.). 
+
+## Solution strategy
+Create a bunch of functions to perform add, subtract, multiply, division or modulo. 
+
+Then take the calculation from the user. 
+
+As the calculator can perform only two number's calculations, you can use the built in ``split()`` method to make the input a list containing three elements.
+
+The input list's first element would be the first number, second element the operator( +,*,/,-,%) and last one the second number.
+
+Then put the numbers in separate variables and call the appropriate function based on the operator.
+
+> The `split()` method is a built in function in python, which splits a string into a list where the string has a space.
+> Exmp: split("2 + 3") will return ["2","+","3"] as result.
+
+Think for a few minutes and try it yourself first.
+
+## The solution
+```python
+def add(num1, num2):
+ return num1 + num2
+ 
+def subtract(num1, num2):
+ return num1 - num2
+ 
+def multiply(num1, num2):
+ return num1 * num2
+ 
+def divide(num1, num2):
+ return num1 / num2
+ 
+def modulo(num1, num2):
+ return num1 % num2
+
+# Inform user that each element in the input should be separated by space.
+print("Give space among the numbers and operator, like: 24 - 5 ")
+
+# Take input from the user
+calc = input("Enter your calculation: ")
+calclist = calc.split()
+num1 = int(calclist[0])
+operation = calclist[1]
+num2 = int(calclist[2])
+
+ 
+result = 0
+if operation == '+':
+ result = add(num1,num2)
+elif operation == '-':
+ result = subtract(num1,num2)
+elif operation == '*':
+ result = multiply(num1,num2)
+elif operation == '/':
+ result = divide(num1,num2)
+elif operation == '%':
+ result = modulo(num1,num2)
+else:
+ print("Please enter: +, -, *, / or %")
+ 
+print(num1, operation, num2, '=', result)
+```
+**[Try it on Programming Hero](https://play.google.com/store/apps/details?id=com.learnprogramming.codecamp)**
+
+
+## How it works
+You saw five functions to add, subtracts, etc. Those are easy.
+
+Then we are taking user input. Then using `split()` we are splitting that and getting two numbers and the operator.
+
+Then we have if-elif-else, based on the operation, we call the right method to perform the task.
+
+That’s it. 
+
+
+ 
+[![Next Page](../assets/next-button.png)](Password-generator.md)
+ 
+
+tags:  `programming-hero`  `python`  `python3`  `problem-solving`  `programming`  `coding-challenge`  `interview`  `learn-python`  `python-tutorial`  `programming-exercises`  `programming-challenges`  `programming-fundamentals`  `programming-contest`  `python-coding-challenges`  `python-problem-solving`
diff --git a/README.md b/README.md
index c2a8c6b..50ce1d9 100644
--- a/README.md
+++ b/README.md
@@ -102,7 +102,8 @@ Here, we will take a real-world coding related problem. We will think about the
 * **[12.2](Harder/Password-generator.md "Password generator")** -   **[Password generator](Harder/Password-generator.md)** 
 * **[12.3](Harder/Password-with-requirements.md "Password with requirements")** -   **[Password with requirements](Harder/Password-with-requirements.md)** 
 * **[12.4](Harder/Permutations.md "Permutations")** -   **[Permutations](Harder/Permutations.md)** 
-* **[12.5](Harder/Simple-Calculator.md "Generate Sentences")** -   **[Generate Sentences](Harder/Simple-Calculator.md)** 
+* **[12.5](Harder/Generate-Sentences.md "Generate Sentences")** -   **[Generate Sentences](Harder/Generate-Sentences.md)**
+* **[12.6](Harder/Advanced-Calculator.md "Advanced calculator")** -   **[Advanced calculator](Harder/Advanced-Calculator.md)**
 
 
 ## 13 -  User Submitted