What I was thinking since you already have a customer base of teachers. You market directly them. You create a product where the teachers create flash cards (math, English, etc)
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They then assign the cards to the students as home work. (The student has to go through the whole deck over and over until he gets all the answers correct.) The teacher is now able to assign home work that grades itself. The students do better on tests because they have memorized the given material. Every one is happy.
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And unlike the bingo cards teachers will pay a monthly fee to use the service. So the revenue is recurring.
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They then assign the cards to the students as home work. (The student has to go through the whole deck over and over until he gets all the answers correct.) The teacher is now able to assign home work that grades itself. The students do better on tests because they have memorized the given material. Every one is happy.
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And unlike the bingo cards teachers will pay a monthly fee to use the service. So the revenue is recurring.