How do I keep a running total of the number of completed children tasks?
I have 8 parent tasks with various numbers of children tasks. How do I keep a running total of the number of completed children tasks?
Best Answers

It kind of depends on how your data is formatted, but if you only have 1 column currently you won't be able to easily add parts of the text together using a formula.
My recommendation would be to have "totaldone" and "totaltocomplete" as columns. The children rows would be integer (number) fields that just count the number of tasks done and the parent row formula would be as below:
=sum(children())
That way you would have a sum of "totaldone" and "totaltocomplete". Then, the formula for the "progress" column would be:
=totaldone@row+" of "&totaltocomplete@row+" Done"
That way both parent and child would display as "x of y Done"
Depending on whether completion is being recorded or calculated, you may be able to hide the extra columns.

Yes. You could use something along the lines of
=COUNTIFS(CHILDREN([Checkbox Column]@row), 1) + " of " + COUNTIFS(CHILDREN([Checkbox Column]@row), OR(@cell = 1, @cell <> 1)) + " Done"
First we count how many children rows are checked. Then we drop in " of ". Then we count the total number of children rows both checked and unchecked. Finally we drop in " Done".
Answers

How are you recording that they are done? Do you have a checkbox column, or a percentage column, or a dropdown column, or.......?

It kind of depends on how your data is formatted, but if you only have 1 column currently you won't be able to easily add parts of the text together using a formula.
My recommendation would be to have "totaldone" and "totaltocomplete" as columns. The children rows would be integer (number) fields that just count the number of tasks done and the parent row formula would be as below:
=sum(children())
That way you would have a sum of "totaldone" and "totaltocomplete". Then, the formula for the "progress" column would be:
=totaldone@row+" of "&totaltocomplete@row+" Done"
That way both parent and child would display as "x of y Done"
Depending on whether completion is being recorded or calculated, you may be able to hide the extra columns.

@Paul Newcome I am using a checkbox column. I believe that I may have found a way to calculate what I need by using additional columns to:
 store the sum of the completed tasks (column15)
 store the sum of the total number of tasks to be completed (column16)
 formula =[Column15]1 + " of " + [Column16]1 + " Done"
Is it possible to a create formula without needing to use additional columns?

Yes. You could use something along the lines of
=COUNTIFS(CHILDREN([Checkbox Column]@row), 1) + " of " + COUNTIFS(CHILDREN([Checkbox Column]@row), OR(@cell = 1, @cell <> 1)) + " Done"
First we count how many children rows are checked. Then we drop in " of ". Then we count the total number of children rows both checked and unchecked. Finally we drop in " Done".