My kids were in a full-on Montessori for two years. "Real" Montessoris do not emphasize memorizing math facts or speed math, which are unfortunately important to master too. I thought it was great for introducing complex ideas like multiplication to very young children, but you really had to work on extra things at home to stay afloat.
I agree that they should just tell you that. The Montessori philosophy is really "follow the child," and I never knew what they did if the child didn't want to read or do math, etc.