By default Windows calculator doesn't support order of operation, to enable the functionality you need to activate the scientific view, let me show you how.
In this day of age, it's very practical to have a Windows 7 installation on your USB key, for many netbooks and devices don't come with CD/DVD drives anymore.
Exchangeable Image File Format (EXIF) data can tell you which camera was used, what focal length, ISO, exposure time was set when taking a photo. Let's see how to look for that data in Windows 7.