D.K.
It is so much better NOT to memorize them but to have her understand them in a concrete way. At my son's Montessori, they used a concept of chains and squares to learn multiplication - which when they truly see what it is - is something children can do at 4-6 years of age. There are specific Montessori materials for learning this concept but this website seems to have printables and demonstrate the concepts. When she can see, feel and manipulate numbers, she will know them. My son did Montessori through kindergarten. The kindergartners were pretty much all multiplying, understood cubes of numbers up to 10 (which cubed is 1000) and could do long division in small groups. He is so so so far ahead of his classmates in a top rated public school because he 'sees' the numbers.
http://blog.montessoriprintshop.com/2012/02/24/skip-count...