Simplify the following text for a Grade 5 native English-speaking person.
Original: With the introduction of PokÃ mon breeding , PokÃ mon are assigned to one or two breeding groups . When a male and female PokÃ mon that share at least one breeding group are left at a PokÃ mon Daycare , they may produce an egg , which will hatch into a young PokÃ mon. .
Simplified: They are the second games in the PokÃ mon series , and increased the number of PokÃ mon to 251 .