4

21. were

22. will cycle

23. am staying

24. didn't use to do

25. taught

26. went, had

27. will arrive

28. didn't have

29. moved

30. Did Jenny go

1. They usually go to the movies.

2. She never listens to classical music.

3. He sometimes reads the newspaper.

4. Sara never smile.

5. She always has rice for dinner.

6. I sometimes drink coffee.

7. I always drink coffee in the morning.

8. We never drink wine.

9. I never smoke.

10. I seldom eat meat.

11. I always eat vegetables and fruits.

12. They sometimes read a book.

2 + 3/4 = 8/4 + 3/4 = 11/4

5/7 : 6 = 5/7 x 1/6 = 5 /42

5 + 2/7 = 35/7 + 2/7 = 37/7

2 - 3/5 = 10/5 - 3/5 = 7/5

5/24 + 7/12 + 5/6 = 5/24 + 14/24 + 20/24 = 39/24

79/36 - 2/4 - 5/6 = 79/36 - 18/36 - 30/36 = 31/36

23/24 x 4/5 = 23/30

7/28 + 6/7 = 7/28 + 24/28 = 31/28

3/4 là \(\dfrac{3}{4}\) nhé bạn, mấy cái kia cũng thế

Thời gian con ốc sên bò lên 1 cây là:

     5 : 9 = 5/9 (phút)

Thời gian con ốc sên bò xuống 1 cây là:

     5 : 15 = 1/3 (phút)

Thời gian con ốc sên bò cả lên và xuống 1 cây là:

     5/9 + 1/3 = 8/9 (phút)

Thời gian con ốc sên bò lên rồi xuống 2525 cây là:

     2525 x 8/9 = 20200/9 (phút)

0,5 + 1 3 + 0,4 + 5 7 + 1 6 - 4 35 = 1/2 + 1/3 + 2/5 + 5/7 + 1/6 - 4/35 = (1/2 + 1/3 + 1/6) + (2/5 + 5/7 - 4/35) = (3/6 + 2/6 + 1/6) + (14/35 + 25/35 - 4/35) = 6/6 + 35/35 = 1 + 1 = 2

is 

0,5 + \(\dfrac{1}{3}\) + 0,4 + \(\dfrac{5}{7}\) + \(\dfrac{1}{6}\) - \(\dfrac{4}{35}\)

= 1/2 + 1/3 + 2/5 + 5/7 + 1/6 - 4/35

= (1/2 + 1/3 + 1/6) + (2/5 + 5/7 - 4/35)

= (3/6 + 2/6 + 1/6) + (14/35 + 25/35 - 4/35)

= 6/6 + 35/35

= 1 + 1

= 2

1. C

2. C

3. C

4. C

5. D

6. B

7. C

8. C

9. A

10. B

11. B

12. A

13. B

14. A

15. A

16. D

17. C

18. A

19. D

20. D

21. A

22. A

23. C

24. A

25. B

26. D

27. A