Yes, you can start that one very early too! Read on some of the suggestions:

• How to Teach Your Child Math: Glen Doman’s Dot Method
• Mathematics PowerPoint Presentations
• Incorporating Math in your Daily Life – Linda Sebec’s approach
• Incorporating Math in Child’s Daily Life – How do YOU do it? – forum members’ suggestions
• Free online game for kids teaching base ten numbers
• RightStart Mathematics: uses the AL Abacus to provide a visual, auditory, and kinesthetic experience. The elementary and intermediate program lessons guide the teacher day-by-day and year-by-year, helping children understand, apply, and enjoy mathematics while surpassing state standards. Highly recommended by many parents at TeachYourBabyToRead yahoo group, many of whom start this homeschooling curriculum right from toddlerhood. More opinions and personal experiences are welcomed.
• Montessory three-part lesson is used for introducing and reinforcing the concept of addition. Can be used for other mathematical operations. Very good video, excellent simple and laconic explanations. Short and very useful: Montessori Introduction to Addition