1. The nine plus nine on the left of cypress is a wooden character, and the ninety-nine on the right is exactly one hundred MINUS one, which is a cypress character.

2. From the profit of each piece to 25% of the cost, we can know that the price is 72* 1.25=90 yuan, so the daily profit is (90 * 0.9-72) * (100 * 2.5) = 2,250 yuan, and the previous daily profit was 72 * 0.25 yuan.

3.6, the formula is n (n- 1)/2, where n represents the number of straight lines.

4. 100! = 100*99*98! , so 100! /98! =9900

5.5 sheets

6.6

7.b