1, (odd minus 3, even is always 2)

2、( 150×3-48)÷2

3.(9 rows and 9 columns, 9×9=8 1)

4 、( B=9，C=8)

5. (2 knives in longitudinal direction and 1 knife in transverse direction)

6, (35÷4=8…3, the number of 4 can only be 8, 9, 9, 9, and there are four kinds: 8999, 9899, 9989, and 9998).

7. (Look at each row, 2 in each row, 3×2=6)

8、(28+26+26=80)

9、(9÷ 1×(6+7)×(8-2)

10, (6+6÷3=8, borrow 1 bottle first, and then return it after drinking, ***9 bottles).

1 1, (the left and right sides are equal to the side length of a square, and 8+6= 14, so the total perimeter is 14+ 14=28).

In this series of numbers, the sum of the 40th digit is ().

The law is 199 repetition, 40÷3= 13… 1, and the sum is13× (1+9)+1= 248.

So tired! The landlord should add points!