Math cards, reading, music, encyclopedic knowledge, all those static activities. I regret I did't know enough about early learning when my child was 3 months old. Now it's so hard to keep her in front of the computer, watching dots ( and may not be effective). And if I bring out math cards, she runs away. When she was 3 months old, she could not even crawl, so she'd have no choice, but to study