Is it possible to save a variable value in Android (in memory), even after closing the application? If so, how?

Is it possible to save a variable value in Android (in memory), even after
closing the application? If so, how?

How is it possible to save a variable value in an Android app? Can the
value be saved in memory? I am planning to save a float value in my
application, so the next time the app is opened, the previous value will
be loaded. How do I go about this? Shared Preferences or something else?