I would also recommend Elizabeth G. Hainstock's book "Teaching Montessori in the Home: The School Years" (and the first part, "The Pre-School Years", which is for children aged up to 5). IIRC, these books are from the early 1970s, but I was blown away by the clarity of the instructions, explanations and drawings. The School Years book is, obviously, aimed at somewhat older children, but it offers really interesting exercises and tools for teaching maths: https://www.amazon.com/Teaching-Montessori-Home-School-Years...
"Classic" version of the book with all the activities, also in PDF form: https://classic.csunplugged.org/books/
I would also recommend Elizabeth G. Hainstock's book "Teaching Montessori in the Home: The School Years" (and the first part, "The Pre-School Years", which is for children aged up to 5). IIRC, these books are from the early 1970s, but I was blown away by the clarity of the instructions, explanations and drawings. The School Years book is, obviously, aimed at somewhat older children, but it offers really interesting exercises and tools for teaching maths: https://www.amazon.com/Teaching-Montessori-Home-School-Years...
Best of luck and have fun!