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.
Some installations or settings changes require you to restart your computer. In most cases you don't need to actually reboot it, you only need to restart the explorer.exe process.
The blurry, transparent background in Notification Center, Control Center, Spotlight and other more options menus on iOS 7 device can make reading experience rather unpleasant.