Simplify the following text for a Grade 7 native English-speaking person.
Original: The MicropÃ dia was introduced in 1974 with 10 volumes having 102,214 short articles , all of which were strictly fewer than 750 words .
Simplified: The MicropÃ dia was introduced in 1974 with 10 books having 102,214 short articles , all of them are less than 750 words .