1. Calculate 2.5× 7.5+1.3× 7.5+45× 0.75 = ().

2.352.46-35.58-65.93-76.07-24.42=( ).

4. Chunhua bought a New Year card and a birthday card with 4 yuan money *** 14, each at 0.35 yuan, each at 0.25 yuan. She should buy a New Year card () and a birthday card ().

5. The number of columns is arranged as follows: the sum of the number100th rows is ().

6. The average of five numbers is 30. If one of the numbers is changed to 50, the average of the five numbers becomes 25. The changed number was originally ().

7. The difference between A and B is 6, and the quotient of A divided by B is also 6. Then a is () and b is ().

8. Four numbers: 1, 2, 3, 4. Take two of them to form a two-digit number. Of the two digits, () is a multiple of 2.

9. A big cube made up of 27 small cubes, with all faces painted red, will have () small cubes painted red on both sides.

10. Floor with the same square brick, 24 m2 96 yuan. If you pave another 40 square meters, you need a square brick ().

1 1. Middle-class children in kindergarten share cookies. If no one divides 5 pieces, there are 22 pieces left; If everyone is divided into 7 pieces, there is still a gap of 18 pieces. The middle class has () children and () cookies.

12. Two groups of students participated in "Science and Technology" activities. The number of people in group A is three times that of group B, while the number of people in group B is 40 less than that of group A, and the number of people who participate in "science and technology" activities is ().

15. If the length and width of a cuboid are increased by 5cm, its area will increase by125cm. The original circumference of this rectangle is () cm.