11. (3 points) The product of any one-digit odd number and any one-digit even number, the number of different products is $\qquad$.

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Note: The last sentence is a note and not part of the translation. The actual translation is above.
11. (3 points) The product of any one-digit odd number and any one-digit even number, the number of different products is $\qquad$ 19.

【Analysis】Since 0 is the smallest even number, 5 odd numbers $(1,3,5,7,9)$ multiplied by 4 even numbers $(2, 4, 6, 8)$
is a total of $4 \times 5=20$ numbers, removing the product of 18 and the product of 6, which are the same, leaves 18, and adding 0, makes 19, according to this solution.

【Solution】Solution: 5 odd numbers $(1,3,5,7,9)$ multiplied by even numbers $(2, 4, 6, 8)$ is a total of $5 \times 4=20$ results, removing $3 \times 6=2 \times 9, 2 \times 3=1 \times 6$ two identical results, leaves 18, and adding 0, makes 19; Answer: There are 19 different products;

Therefore, the answer is: 19.
【Comment】The key is not to forget to subtract the identical products, note that 0 is an even number.