Simplify the following text for a Grade 10 native English-speaking person.
Original: In some cases , for instance the Penny Reds of Great Britain and modern United States plate number coils , the plate numbers appear in the stamps themselves , but the more common practice is to include the number in the margin of each sheet , sometimes alongside the name of the printer .
Simplified: Sometimes the plate numbers appear in the stamps themselves , but the more common practice is to include the number in the margin of each sheet , frequently alongside the name of the printer .