expression.error when trying to add up numerics in Power Query

[AJPF]

I have a variable called "Start" which I am trying to sum down the entire column.   It contains only 0 or 1 and it's formatted as a whole number. 

In Power Query I have: 

= Table.AddColumn(#"PREVIOUS STEP", "Start Total", each List.Sum([Start]))

but I keep getting the message: 

"Expression.Error: We cannot convert the value 1 to type List.
Details:
Value=1
Type=[Type]"

Why can I not add numeric values? 

Is there another way of doing this?  I don't care whether I do it in Power Query or as a new measure. 

[Jimmy801 · Accepted solution]

Hello @AJPF 

you get this error because List.Sum is expecting a list, but you are feeding the function a number. I don't know whats the goal you are trying to achieve. I suppose you would like to sum the whole column start. This however would result in the same number in every row, as you are not filter the column before. If this is it what you would like to achive use this formula

= Table.AddColumn(#"PREVIOUS STEP", "Start Total", each List.Sum(#"PREVIOUS STEP"[Start]))

If this post helps or solves your problem, please mark it as solution (to help other users find useful content and to acknowledge the work of users that helped you)
Kudoes are nice too

Have fun

Jimmy