A=(2+2^2)+...+(2^59+2^60) 
=2(1+2)+...+2^59(1+2) 
=3(2+2^3+...+2^59) 
nên A chia hết cho 3. 
A= (2+2^2+2^3)+...+(2^58+2^59+2^60) 
=2(1+2+2^2)+...+2^58(1+2+2^2) 
=7(2+2^4+..+2^58) 
nên A chia hết cho 7 
A= (2+2^2+2^3+2^4)+....+(2^57+2^58+2^59+2^6... 
=2(1+2+2^2+2^3)+....+2^57(1+2+2^2+2^3)... 
=15(2+2^5+...+2^57) 
nên A chia hết cho 15

tick di ban

Choose A, B, C or D on your answer sheet to indicate the word that is pronounced differently from the others in each of the following questions.

A. misses

B.  hates

C.  messages

D. closes

1. Would you like to have breakfast with eggs, children?

2. I'd like to join the clubs.

3. I'd like to buy some stamps to overseas mail.

4. It has a lot, about one thousand.

5. In Vietnam, there is no lesson on Saturday.

6. You can find math books on the rack in the middle.

7. Look! The teacher is coming here.

8. She studies maps in Geography.

9. Ba can fix the lights.

10. He enjoys drawing pictures.

11. Mai learns to play the piano in her free time.

12. Where is your brother? - He is studying in the library.

13. Minh usually plays volleyball after school. Now he is playing volleyball in the sport ground.

14. Children shouldn't stay up late.

15. He enjoys collecting stamps and coins.

16. Next year, my sister will be a teacher.

17. Let's go to the English club.

18. What do you like doing during your vacation?

19. It's ten to seven. Hurry up or you will be late for school.

20. Hoa is having breakfast with her uncle now.

21. Mr. Jones gets seven public holidays each year.

22. Mai loves playing the piano.

23. You will have lots of friends soon.

24. Students should review their work before tests.

25. Look ! The children are riding their bikes .

26. Could you show me the way to the bus stop ?

27. Hoa needs to buy a phone card.

28. He Nam wants to send this postcard to his pen pal.

29. We would like to visit Ngoc Sơn Temple.

GOOD LUCK!^_^

Cho dạng đúng của từ trong ngoặc :

1. (you/be) Will you be free next Sunday morning, Tan ? No, my brother and I (visit) will visit/ am going to visit our grandparents.

MK nghĩ là hs lớp 7 nên chia thì tương lai đơn bn ah( will visit).

b, I prefer the city to the country .

c, I prefer outdoor activities to indoor activities .

d, I prefer the cold weather to the hot weather .

e, I prefer pop music to traditional music (nhạc cổ điển)

f, I prefer computer to books .

MẪU CÂU DÙNG VỚI '' PREFER''

1. prefer doing sth to doing sth :thích làm........hơn làm.......

2. prefer sth to sth :thích cái..........hơn cái..