[ Arithmetic. Mental calculation, etc.]

Prosperous Mole in autumn dug up 8 bags of grain. For each winter month, he needs either 3 bags of grain or 1 bag of grain and 3 bags of millet. Mole can trade with other moles 1 bag of grain for 2 bags of millet. But his burrow cannot hold more than 12 bags, and in winter Mole does not leave his burrow and cannot engage in trading. Help him make provisions for three months.

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A mole can exchange 3 bags of grain for 6 bags of millet, then in its burrow there will be 11 bags: 5 bags of grain and 6 bags of millet. For one month, it will spend 3 bags of grain, and for each of the other two - 1 bag of grain and 3 bags of millet.