[tex]\qquad \qquad\huge \underline{\boxed{\sf Anѕwєr}}[/tex]
To get the number of terms in an expression we have to add the like terms, and after that the different terms separated by mathematical operators (+ and -) are the required number of terms !
That is :
[tex]\qquad \sf \dashrightarrow \: 55 + 14m - 2n + 3p[/tex]
here, since we don't have like terms, let's skip the first part.
So, total number of terms = 4