The long way to do this is to have
4*4*4 *4*4*4 *4
so we have 7 copies of '4' multiplied together
Typing this into your calculator leads to
4*4*4 *4*4*4 *4 = 16384
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The shortcut is to use exponents
Writing 4^7 means we have a base of 4 and an exponent of 7.
Saying 4^7 is the same as saying

To enter in your calculator, you would hit the button labeled

So you'll type 4, then the
button followed by 7
Your calculator will then show 16384 as a result.
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Side note: you could compute all this by hand using pencil & paper, but to me that seems like tedious busy work (so why not use a calculator to be efficient).