Question: I have excel like this.

[![enter image description here](https://i.stack.imgur.com/U4QjK.png)](https://i.stack.imgur.com/U4QjK.png)

I want end result like this

[![enter image description here](https://i.stack.imgur.com/ogl0A.png)](https://i.stack.imgur.com/ogl0A.png)

Means

I want to Put formula in column c to get grade based on what is in column B.

If in B is Check mark, C should show "A"

If in B is Cross mark, C should show "B"

If in B is Question mark, C should show "C"

Answer: 
To answer my own question: **This is a bug in the Windows 10 calculator**. 

The problem did not exist in Windows 7, and it was NOT fixed in the first big update for Windows 10. As of December 2015, the bug is still there.

As usual there is no official acknowledgement. However, for a discussion on the Microsoft servers, see e.g. <https://answers.microsoft.com/en-us/windows/forum/windows_7-winapps/windows-calculator-decimal-separator-is-always/d6e80dc7-9738-4a61-8457-c5e5d28beeb8?db=5&auth=1>
As you said yourself, this is a problem with the calculator in Windows 10 that hasn't been fixed yet. What I did to solve this for me was to [install the Windows 7/8 calculator](http://winaero.com/blog/get-calculator-from-windows-8-and-windows-7-in-windows-10/).