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Flash cards are great for building vocabulary. They are also great for memorizing dates and events.
Some people use them for memorizing formulas.
In the good old days, you had to pay to buy a box of flash cards. You still can. This is convenient if you find a box that covers what you want to learn. But these days, you can create your own. This is great for specialized lists that no one sells in a packaged set.
What does it cost? Nothing, except for your time.
For a guide to what the program offers, go here.
I recommend that students get up and running with English vocabulary cards, beginning in the 5th grade. If the student decides to start college as a freshman rather than by using CLEP exams to enter as a junior, the SAT or ACT exam is important as a student-screening device. Use flash cards to start increasing the verbal score.
I strongly recommend that you encourage your children to become proficient with this program. Who knows? Maybe one of your children can teach you how it works.
Ron Paul Curriculum