If ''M'' means ''-'', ''N'' means ''/'', ''O'' means ''+'', and ''P'' means ''*''; then find the value of the following:
21 N 7 O 9 P 10 M 13
80
(21 / 7) + (9 * 10) - 13 = 3 + 90 - 13 = 80
80
(21 / 7) + (9 * 10) - 13 = 3 + 90 - 13 = 80