Simplify 5m - 13n - n + 4m.

Group similar terms,

5m+4m -13n-n
and work out the sum of similar terms.

12 +y

----------
36+w

To simplify the given expression, we can combine like terms. Like terms are terms that have the same variable raised to the same power.

Given expression: 5m - 13n - n + 4m

Now, let's combine the terms with variable "m" and the terms with variable "n":

(5m + 4m) + (-13n - n)

Combining "m" terms:
5m + 4m = 9m

Combining "n" terms:
-13n - n = -14n

Now we can rewrite the simplified expression:
9m - 14n

Therefore, the simplified form of 5m - 13n - n + 4m is 9m - 14n.