The game is simple: you're asked a question and given four possible answers. If you guess the right one, you earn 10 grains of rice. If you guess wrong, you don't. Either way, you keep going.
The game is always challenging (but not too hard), because if you get a lot of questions right, it gives you harder questions, and if you get a lot of questions wrong, it gives you easier questions. So you always end up being at a level where you get some questions right and some questions wrong. It makes you want to try one more . . . and one more . . . and one more.
You can set up an account to keep track of how much rice you've won—and to challenge your friends!
You can choose from different subjects:
For younger students, I recommend English Vocabulary, English Grammar, and Multiplication Table.
For older students, I recommend English Vocabulary, English Grammar, Spanish (if they're taking Spanish!), and SAT. The SAT practice questions cover both language arts and math. Great practice!
Here's a video made by some high school students who really like Free Rice!