Welcome to TI|BD! First, I would suggest reading over the starter-kit as it contains a lot of information about basic programming, and covers a few of the more advanced techniques. To do what you want to do, you need to use one or moreroutines. The first routine you will need is the index-finder routine, which returns the index of a number in a list. You will then also need to use a pseudo-routine to remove that index from the list. Here is how it basically will work:

```
* Input the number you want to remove
* Find the index of that number
* Take everything after that index and move it up 1 index
* Remove the last element from the list
```

Now in reality, its a little more complicated than that because of what is known as error-proofing. Error-proofing makes it so that a wrong input won't break the program. Here is how I would code the solution. Note that this solution is not optimized, and is meant to help show how things can be done in TI-Basic. This also is not fully error-proofed, but does show a small amount

```
Lbl R //give us a return point
Prompt X //ask the user for input of the number they want removed
X→L₁(1+dim(L₁ //add it onto the end of the list to ensure the number is always found
1+sum(not(cumSum(L₁=X))) //find the number
Ans→P //store the position of the number
If P=dim(L₁:dim(L₁)-1→dim(L₁ //if the number is at the very end of the list, we just added it; therefore it never existed in the list, so remove it
If P>dim(L₁ //if the position of the number is greater than the length of the list it creates an impossibility, this comes from when we removed the number that was not in the original list
Goto R //go back to the beginning and try again
For(E,P+1,dim(L₁) //start at 1 above the position and go to the end of the list
L₁(E)→L₁(E-1) //move the data from that position down 1 position
End
dim(L₁)-2→dim(L₁ //remove the last 2 items from the list
L₁ //display the list
```