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What are the interlayer numbers from 100 to 100 in mathematics?
8 1.

When both the unit and the hundred digits are 1, the change of the ten digits is 0~9, and the number 1 needs to be removed, so there are nine combinations.

The arrangement is: 10 1, 12 1 31,14 1,15/kloc.

By analogy, when both the unit and the hundred digits are 9, the change of the ten digits is 0~8, and the number of combinations is 9.

909、9 19、929、939、949、959、969、979、989;

To sum up, a * * * has 8 1 sandwich cookies.