According to the mathematical calculation, Kobayashi has 9 sheep, 1 1 white rabbit, 7 gray rabbits,1* * 9 sheep, 18 rabbits, or 27 small animals.

When calculating addition, from the lower order, which digit adds up to 10 will be added to the previous digit, and when calculating subtraction, it will be subtracted from the lower order. If it is not enough, it will be borrowed from the previous digit as 10.