Diện tích nền nhà là:

      5 x 8 = 40 (m²) = 400000 (cm²)

Diện tích một viên gạch là:
      20 x 20 = 400 (cm²) 

Cần số viên gạch là:

      400000 : 400 = 1000 (viên)

                           Đ/S:

(x - 8,9) - 2,4 = 3,7

x - 8,9 = 3,7 + 2,4

x - 8,9 = 6,1

x = 6,1 + 8,9

x = 15

GTNN của biểu thức là 2000

+ (-8) = -8 

Làm tắt tí =)))

8,56 dm² = 856 cm²

0,42 m² = 42 dm²

1,8 ha = 18000 m²

2,7 dm² = 2 dm² 70 cm²

6,9 m² = 6 m² 90 dm²

-1 - 2 - 3 - 4 - 5 + 7

= (-1 - 2 - 4 + 7) + (3 - 5)

= 0 - 8 = -8

1. C

2. D

3. D

4. D

5. B

6. D

7. A 

8. B

9. B

10. C

I’m sorry, but you have to cook dinner………………

         A. myself                     B. himself                 C. yourself                D. ourselves

      2. They hope they can…………natural resources.

         A. collect                      B. plant                      C. keep                      D. save

3. Tom is 16. He isn^’t …….. to drive a car.

  A. enough young        B. young enough    C. enough old          D. old enough

4. When my uncle was young, he used ……….. fishing on Sundays.

  A. go                              B. went                      C. going                     D. to go

5.     My sister has been a student at this school…………two years.

 A. since                         B. for                        C. in                            D. about

      6.  Many young people are fond …………….playing football.

         A. in                             B. on                         C. at                           D. of

      7. You should go to the………………to buy some fish and vegetables

         A. market                    B. post office           C. kitchen                 D. theater

      8. You are not allowed to go ..................... the museum without paying.

         A. outside                    B. inside                    C. upstairs                D. downstairs

      9. He does morning exercises regularly ..................improve his health.

         A. in order for            B. so as to                 C. so that                  D. in order that

      10. Customers can shop in .........................in the new shopping mall in town.

         A. concern                  B. convenience       C. comfort                D. community