@AjithPreit8216 PEMDAS. You do Parenthesis (not relevant here), exponents, Multiplication and Division (from left to right) then Addition and Subtraction (from left to right)
So:
4^2 = 16
4x4 = 16
16/4 = 4
now we get:
16 - 4 + 4.
From left to right:
12 + 4 = 16