Solve for $m$. \[ 20+m=n \] \[ m= \]

Step 1 ：The question is asking to solve for $m$ in the equation $20+m=n$.

Step 2 ：To find the value of $m$, we need to isolate $m$ on one side of the equation.

Step 3 ：We can do this by subtracting $20$ from both sides of the equation.

Step 4 ：The solution to the equation is $m = n - 20$.

Step 5 ：Final Answer: \(\boxed{n - 20}\)