With the term "elementary operation" we mean to add two digits of the decimal system and to write the result and the carries. How many elementary operations do we need for the addition of two numbers with $n$ digits?
(we consider that the addition of two digits together with the carry that comes from previous operations is one elementary operation)
If we add two numbers with $n$ digits, we add at each step two digits, one of each number, and possibly a carry. That means that we need $n$ elementary operations.
Is this correct?
How could we show that the addition of any two numbers with $n$ digits each one of them, cannot be done with less than $n$ steps/elementary operations?