For the month of September, you can get free early access to Boethius, a smart flashcard app for classical homeschooling now entering open beta. Currently, the grammar, arithmetic, and astronomy exercises are roughly at the 2nd through 4th grade level. Some unique features include (1) software-grading, so it doesn't rely on the student to judge whether their answer was "close enough", (2) spaced-repetition (progressively decreasing review frequency for correct answers and the opposite for incorrect ones) to maximize long-term retention of facts/skills, and (3) spoken exercises (including with correct medieval Latin pronunciation). I'm the sole developer of the app and would love to hear any feedback. Thanks!