In a group A there were 20 people and in a group B there were 21.
How to suitably express the quantitative difference between the groups? Can I say "In a group B there was one man (person) more or "In a group B there was one man (person) in addition“? At first glance a trivial question but I am really not sure.
If the groups were of people:
Group B was larger than Group A by one person.
A was {comparative} than B by {quantifier} {unit of measure [pluralized as necessary]}
The sedan was longer than the hatchback by 14 inches.
The new highrise apartments were taller than the old ones by three stories.
The current textbook is shorter than the former by two chapters.
Next month's shipment will be lighter than this one by a few tons.
P.S. If there are supposed to be 21 people in the group, as there are supposed to be 52 cards in a deck, but one is missing:
The group was shy one person.
The deck was shy two jacks.
The deck had one ace too many.