Given the list in A1:A6, where some entries consist of a single number and some of a grouping of numbers (where e.g. 13-16 represents 13, 14, 15 and 16), the challenge this week is to come up with a single formula in D1 which, when copied down an arbitrary number of rows, produces a list of all individual, ungrouped numbers from the list in A1:A6, as here:

The formula is to return a blank in rows beyond the expected number of returns. What’s more, this *must* be done via reference to a second formula, in C1, also to be derived and whose value is to equal the total expected number of non-blank entries to be returned in column D for any given dataset.