36.You shouldn’t stay up late to play computer games.

37.The bus is behind the motorbike.

38.Jack’s typing is better than Tom’s.

39.There are not any flowers in my house.

40.We mustn’t throw rubbish around our school.

1.You shouldn’t swim immediately after a meal.

2.Parents should give lucky money to children at Tet.

3.No one should break things on the first day of New Year.

4.People should not drink a lot of wine and beer during Tet.

5.You should not go out alone at night.

6.There is not any homework during Tet.

7.We have no balloons to decorate our rooms.

41.Hoa is buying flowers for her father's birthday at the moment.

42.Nobody in my class is better at Maths than Minh.

43.At twelve o'clock at night, everyone says "Happy New Year" to their friends and relatives and wishes them good luck.

44.How often do you go fishing with your father?

45.The new market is inconvenient because it is far from our flat building.

Ta có:

  300=22×3×52.

  240=24×3×5.

  420=22×3×5×7.

=UCLN=22×3×5=4×3×5=60.

   Vậy số lượng phần quà nhiều nhất là 60 phần quà.

a) 2023+64+(−2023)+36=100

b,(45−17)−(40−157+45)=100

c,20230−3⋅[52⋅10−(23−13)⋅2]=18730

sai câu c

=60,97

wthhhh

   Khóa chính trong cơ sở dữ liệu quan hệ có vai trò xác định duy nhất mỗi bản ghi trong bảng, đảm bảo tính toàn vẹn dữ liệu và không trùng lặp. Nó cũng giúp tạo mối quan hệ giữa các bảng thông qua khóa ngoại và tăng hiệu suất truy vấn nhờ việc tạo chỉ mục.