This question is actually fairly simple...I'll work it out for you.
P + MN
P= 4
M = 5
N = 3
Now you substitute or 'plug-in' the numbers.
4 + 5 x 3
The rule of P.E.M.D.A.S states multiplication comes before addition, so 5 x 3 = 15.
Add 4 to 15, you get 19.
Answer : 19.
:)