Answer
$35-n$
Work Step by Step
Let us call the other number $z$.
Since the sum of the two numbers is $35$, we can write the following equation: $z+n=35$
We must solve the equation for $z$, because we are looking for the other number. To do so, we subtract $n$ from each side of the equation: $z=35-n$
Since the other number is equal to $z$, the other number is $35-n$