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.
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.
If you need, besides major accounts, an extra account with limited access to data, you can add Windows 8 Guest account. The process is almost the same as in Windows 7.