In taking a physical inventory at the end of year 2011, Nadir Company forgot to count certain

Question:

In taking a physical inventory at the end of year 2011, Nadir Company forgot to count certain units. Explain how this error affects the following:
(a) 2011 cost of goods sold,
(b) 2011 gross profit,
(c) 2011 net income,
(d) 2012 net income,
(e) The combined two-year income, and
(f) Income for years after 2012.