A sentence reads, “Robert Mary Jane Andrea Lee Ann and I should be arriving.” Not knowing how the different names are actually connected, how many commas must you add to the sentence to show that there will be five people arriving?
Using the Oxford comma principle, four.
Since it is not known how the names are actually connected, this is only to illustrate:
"Robert, Mary Jane, Andrea, Lee Ann, and I should be arriving."
For those who do not hold to the Oxford comma principle, three commas would suffice.